Three-dimensional structures having feature sizes smaller than a minimum feature size and methods for fabricating

ABSTRACT

Embodiments of multi-layer three-dimensional structures and formation methods provide structures with effective feature (e.g. opening) sizes (e.g. virtual gaps) that are smaller than a minimum feature size (MFS) that exists on each layer as a result of the formation method used in forming the structures. In some embodiments, multi-layer structures include a first element (e.g. first patterned layer with a gap) and a second element (e.g. second patterned layer with a gap) positioned adjacent the first element to define a third element (e.g. a net gap or opening resulting from the combined gaps of the first and second elements) where the first and second elements have features that are sized at least as large as the minimum feature size and the third element, at least in part, has dimensions or defines dimensions smaller than the minimum feature size.

RELATED APPLICATIONS

This claims benefit of U.S. Provisional Patent Application No.60/506,016, filed Sep. 24, 2003, which is incorporated herein byreference as if set forth in full herein.

FIELD OF THE INVENTION

Some embodiments of the invention relate to micro-scale or meso-scaledevices with effective feature sizes that are smaller than a minimumfeature size associated with forming individual layers while otherembodiments are directed to methods for fabricating such devices andmore particularly to electrochemical fabrication methods.

BACKGROUND OF THE INVENTION

A technique for forming three-dimensional structures (e.g. parts,components, devices, and the like) from a plurality of adhered layerswas invented by Adam L. Cohen and is known as ElectrochemicalFabrication. It is being commercially pursued by Microfabrica™ Inc.(formerly MEMGen® Corporation) of Burbank, Calif. under the name EFAB™.This technique was described in U.S. Pat. No. 6,027,630, issued on Feb.22, 2000. This electrochemical deposition technique allows the selectivedeposition of a material using a unique masking technique that involvesthe use of a mask that includes patterned conformable material on asupport structure that is independent of the substrate onto whichplating will occur. When desiring to perform an electrodeposition usingthe mask, the conformable portion of the mask is brought into contactwith a substrate while in the presence of a plating solution such thatthe contact of the conformable portion of the mask to the substrateinhibits deposition at selected locations. For convenience, these masksmight be generically called conformable contact masks; the maskingtechnique may be generically called a conformable contact mask platingprocess. More specifically, in the terminology of Microfabrica™ Inc.(formerly MEMGen® Corporation) of Burbank, Calif. such masks have cometo be known as INSTANT MASKS™ and the process known as INSTANT MASKINGor INSTANT MASK™ plating. Selective depositions using conformablecontact mask plating may be used to form single layers of material ormay be used to form multi-layer structures. The teachings of the '630patent are hereby incorporated herein by reference as if set forth infull herein. Since the filing of the patent application that led to theabove noted patent, various papers about conformable contact maskplating (i.e. INSTANT MASKING) and electrochemical fabrication have beenpublished:

-   (1) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.    Will, “EFAB: Batch production of functional, fully-dense metal parts    with micro-scale features”, Proc. 9th Solid Freeform Fabrication,    The University of Texas at Austin, p161, August 1998.-   (2) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.    Will, “EFAB: Rapid, Low-Cost Desktop Micromachining of High Aspect    Ratio True 3-D MEMS”, Proc. 12th IEEE Micro Electro Mechanical    Systems Workshop, IEEE, p244, January 1999.-   (3) A. Cohen, “3-D Micromachining by Electrochemical Fabrication”,    Micromachine Devices, March 1999.-   (4) G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P.    Will, “EFAB: Rapid Desktop Manufacturing of True 3-D    Microstructures”, Proc. 2nd International Conference on Integrated    MicroNanotechnology for Space Applications, The Aerospace Co., April    1999.-   (5) F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, 3rd International    Workshop on High Aspect Ratio MicroStructure Technology (HARMST'99),    June 1999.-   (6) A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P.    Will, “EFAB: Low-Cost, Automated Electrochemical Batch Fabrication    of Arbitrary 3-D Microstructures”, Micromachining and    Microfabrication Process Technology, SPIE 1999 Symposium on    Micromachining and Microfabrication, September 1999.-   (7) F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, MEMS Symposium, ASME 1999    International Mechanical Engineering Congress and Exposition,    November, 1999.-   (8) A. Cohen, “Electrochemical Fabrication (EFAB™)”, Chapter 19 of    The MEMS Handbook, edited by Mohamed Gad-EI-Hak, CRC Press, 2002.-   (9) Microfabrication—Rapid Prototyping's Killer Application”, pages    1-5 of the Rapid Prototyping Report, CAD/CAM Publishing, Inc., June    1999.

The disclosures of these nine publications are hereby incorporatedherein by reference as if set forth in full herein.

The electrochemical deposition process may be carried out in a number ofdifferent ways as set forth in the above patent and publications. In oneform, this process involves the execution of three separate operationsduring the formation of each layer of the structure that is to beformed:

-   -   1. Selectively depositing at least one material by        electrodeposition upon one or more desired regions of a        substrate.    -   2. Then, blanket depositing at least one additional material by        electrodeposition so that the additional deposit covers both the        regions that were previously selectively deposited onto, and the        regions of the substrate that did not receive any previously        applied selective depositions.    -   3. Finally, planarizing the materials deposited during the first        and second operations to produce a smoothed surface of a first        layer of desired thickness having at least one region containing        the at least one material and at least one region containing at        least the one additional material.

After formation of the first layer, one or more additional layers may beformed adjacent to the immediately preceding layer and adhered to thesmoothed surface of that preceding layer. These additional layers areformed by repeating the first through third operations one or more timeswherein the formation of each subsequent layer treats the previouslyformed layers and the initial substrate as a new and thickeningsubstrate.

Once the formation of all layers has been completed, at least a portionof at least one of the materials deposited is generally removed by anetching process to expose or release the three-dimensional structurethat was intended to be formed.

The preferred method of performing the selective electrodepositioninvolved in the first operation is by conformable contact mask plating.In this type of plating, one or more conformable contact (CC) masks arefirst formed. The CC masks include a support structure onto which apatterned conformable dielectric material is adhered or formed. Theconformable material for each mask is shaped in accordance with aparticular cross-section of material to be plated. At least one CC maskis needed for each unique cross-sectional pattern that is to be plated.

The support for a CC mask is typically a plate-like structure formed ofa metal that is to be selectively electroplated and from which materialto be plated will be dissolved. In this typical approach, the supportwill act as an anode in an electroplating process. In an alternativeapproach, the support may instead be a porous or otherwise perforatedmaterial through which deposition material will pass during anelectroplating operation on its way from a distal anode to a depositionsurface. In either approach, it is possible for CC masks to share acommon support, i.e. the patterns of conformable dielectric material forplating multiple layers of material may be located in different areas ofa single support structure. When a single support structure containsmultiple plating patterns, the entire structure is referred to as the CCmask while the individual plating masks may be referred to as“submasks”. In the present application such a distinction will be madeonly when relevant to a specific point being made.

In preparation for performing the selective deposition of the firstoperation, the conformable portion of the CC mask is placed inregistration with and pressed against a selected portion of thesubstrate (or onto a previously formed layer or onto a previouslydeposited portion of a layer) on which deposition is to occur. Thepressing together of the CC mask and substrate occur in such a way thatall openings, in the conformable portions of the CC mask contain platingsolution. The conformable material of the CC mask that contacts thesubstrate acts as a barrier to electrodeposition while the openings inthe CC mask that are filled with electroplating solution act as pathwaysfor transferring material from an anode (e.g. the CC mask support) tothe non-contacted portions of the substrate (which act as a cathodeduring the plating operation) when an appropriate potential and/orcurrent are supplied.

An example of a CC mask and CC mask plating are shown in FIGS. 1A-1C.FIG. 1A shows a side view of a CC mask 8 consisting of a conformable ordeformable (e.g. elastomeric) insulator 10 patterned on an anode 12. Theanode has two functions. FIG. 1A also depicts a substrate 6 separatedfrom mask 8. One is as a supporting material for the patterned insulator10 to maintain its integrity and alignment since the pattern may betopologically complex (e.g., involving isolated “islands” of insulatormaterial). The other function is as an anode for the electroplatingoperation. CC mask plating selectively deposits material 22 onto asubstrate 6 by simply pressing the insulator against the substrate thenelectrodepositing material through apertures 26 a and 26 b in theinsulator as shown in FIG. 1B. After deposition, the CC mask isseparated, preferably non-destructively, from the substrate 6 as shownin FIG. 1C. The CC mask plating process is distinct from a“through-mask” plating process in that in a through-mask plating processthe separation of the masking material from the substrate would occurdestructively. As with through-mask plating, CC mask plating depositsmaterial selectively and simultaneously over the entire layer. Theplated region may consist of one or more isolated plating regions wherethese isolated plating regions may belong to a single structure that isbeing formed or may belong to multiple structures that are being formedsimultaneously. In CC mask plating as individual masks are notintentionally destroyed in the removal process, they may be usable inmultiple plating operations.

Another example of a CC mask and CC mask plating is shown in FIGS.1D-1F. FIG. 1D shows an anode 12′ separated from a mask 8′ that includesa patterned conformable material 10′ and a support structure 20. FIG. 1Dalso depicts substrate 6 separated from the mask 8′. FIG. 1E illustratesthe mask 8′ being brought into contact with the substrate 6. FIG. 1Fillustrates the deposit 22′ that results from conducting a current fromthe anode 12′ to the substrate 6. FIG. 1G illustrates the deposit 22′ onsubstrate 6 after separation from mask 8′. In this example, anappropriate electrolyte is located between the substrate 6 and the anode12′ and a current of ions coming from one or both of the solution andthe anode are conducted through the opening in the mask to the substratewhere material is deposited. This type of mask may be referred to as ananodeless INSTANT MASK™ (AIM) or as an anodeless conformable contact(ACC) mask.

Unlike through-mask plating, CC mask plating allows CC masks to beformed completely separate from the fabrication of the substrate onwhich plating is to occur (e.g. separate from a three-dimensional (3D)structure that is being formed). CC masks may be formed in a variety ofways, for example, a photolithographic process may be used. All maskscan be generated simultaneously, prior to structure fabrication ratherthan during it. This separation makes possible a simple, low-cost,automated, self-contained, and internally-clean “desktop factory” thatcan be installed almost anywhere to fabricate 3D structures, leaving anyrequired clean room processes, such as photolithography to be performedby service bureaus or the like.

An example of the electrochemical fabrication process discussed above isillustrated in FIGS. 2A-2F. These figures show that the process involvesdeposition of a first material 2 which is a sacrificial material and asecond material 4 which is a structural material. The CC mask 8, in thisexample, includes a patterned conformable material (e.g. an elastomericdielectric material) 10 and a support 12 which is made from depositionmaterial 2. The conformal portion of the CC mask is pressed againstsubstrate 6 with a plating solution 14 located within the openings 16 inthe conformable material 10. An electric current, from power supply 18,is then passed through the plating solution 14 via (a) support 12 whichdoubles as an anode and (b) substrate 6 which doubles as a cathode. FIG.2A, illustrates that the passing of current causes material 2 within theplating solution and material 2 from the anode 12 to be selectivelytransferred to and plated on the cathode 6. After electroplating thefirst deposition material 2 onto the substrate 6 using CC mask 8, the CCmask 8 is removed as shown in FIG. 2B. FIG. 2C depicts the seconddeposition material 4 as having been blanket-deposited (i.e.non-selectively deposited) over the previously deposited firstdeposition material 2 as well as over the other portions of thesubstrate 6. The blanket deposition occurs by electroplating from ananode (not shown), composed of the second material, through anappropriate plating solution (not shown), and to the cathode/substrate6. The entire two-material layer is then planarized to achieve precisethickness and flatness as shown in FIG. 2D. After repetition of thisprocess for all layers, the multi-layer structure 20 formed of thesecond material 4 (i.e. structural material) is embedded in firstmaterial 2 (i.e. sacrificial material) as shown in FIG. 2E. The embeddedstructure is etched to yield the desired device, i.e. structure 20, asshown in FIG. 2F.

Various components of an exemplary manual electrochemical fabricationsystem 32 are shown in FIGS. 3A-3C. The system 32 consists of severalsubsystems 34, 36, 38, and 40. The substrate holding subsystem 34 isdepicted in the upper portions of each of FIGS. 3A to 3C and includesseveral components: (1) a carrier 48, (2) a metal substrate 6 onto whichthe layers are deposited, and (3) a linear slide 42 capable of movingthe substrate 6 up and down relative to the carrier 48 in response todrive force from actuator 44. Subsystem 34 also includes an indicator 46for measuring differences in vertical position of the substrate whichmay be used in setting or determining layer thicknesses and/ordeposition thicknesses. The subsystem 34 further includes feet 68 forcarrier 48 which can be precisely mounted on subsystem 36.

The CC mask subsystem 36 shown in the lower portion of FIG. 3A includesseveral components: (1) a CC mask 8 that is actually made up of a numberof CC masks (i.e. submasks) that share a common support/anode 12, (2)precision X-stage 54, (3) precision Y-stage 56, (4) frame 72 on whichthe feet 68 of subsystem 34 can mount, and (5) a tank 58 for containingthe electrolyte 16. Subsystems 34 and 36 also include appropriateelectrical connections (not shown) for connecting to an appropriatepower source for driving the CC masking process.

The blanket deposition subsystem 38 is shown in the lower portion ofFIG. 3B and includes several components: (1) an anode 62, (2) anelectrolyte tank 64 for holding plating solution 66, and (3) frame 74 onwhich the feet 68 of subsystem 34 may sit. Subsystem 38 also includesappropriate electrical connections (not shown) for connecting the anodeto an appropriate power supply for driving the blanket depositionprocess.

The planarization subsystem 40 is shown in the lower portion of FIG. 3Cand includes a lapping plate 52 and associated motion and controlsystems (not shown) for planarizing the depositions.

Another method for forming microstructures from electroplated metals(i.e. using electrochemical fabrication techniques) is taught in U.S.Pat. No. 5,190,637 to Henry Guckel, entitled “Formation ofMicrostructures by Multiple Level Deep X-ray Lithography withSacrificial Metal layers”. This patent teaches the formation of metalstructure utilizing mask exposures. A first layer of a primary metal iselectroplated onto an exposed plating base to fill a void in aphotoresist, the photoresist is then removed and a secondary metal iselectroplated over the first layer and over the plating base. Theexposed surface of the secondary metal is then machined down to a heightwhich exposes the first metal to produce a flat uniform surfaceextending across the both the primary and secondary metals. Formation ofa second layer may then begin by applying a photoresist layer over thefirst layer and then repeating the process used to produce the firstlayer. The process is then repeated until the entire structure is formedand the secondary metal is removed by etching. The photoresist is formedover the plating base or previous layer by casting and the voids in thephotoresist are formed by exposure of the photoresist through apatterned mask via X-rays or UV radiation.

Even though electrochemical fabrication as taught and practiced to date,has greatly enhanced the capabilities of microfabrication, and inparticular added greatly to the number of layers that can beincorporated into a structure and to the speed and simplicity in whichsuch structures can be made, room for enhancing the state ofelectrochemical fabrication exists. In particular, a need exists fordevices with improved feature resolution, methods for reliably formingsuch devices, and/or methods for providing enhanced feature resolution.

SUMMARY OF THE DISCLOSURE

It is an object of some embodiments of the invention to providemicro-scale or meso-scale devices having effective features sizes whichare smaller than generally believed formable.

It is an object of some embodiments of the invention to provide improvedelectrochemical fabrication methods that allow effective features sizesof structures to be smaller than a minimum feature sizes.

It is an object of some embodiments of the invention to provide morereliable electrochemical fabrication methods for forming structures witheffective features sizes that are less than a minimum feature size.

Other objects and advantages of various embodiments of the inventionwill be apparent to those of skill in the art upon review of theteachings herein. The various aspects of the invention, set forthexplicitly herein or otherwise ascertained from the teachings herein,may address one or more of the above objects alone or in combination, oralternatively may address some other object of an embodiment of theinvention ascertained from the teachings herein. It is not necessarilyintended that all objects be addressed by any single aspect of theinvention even though that may be the case with regard to some aspects.

In a first aspect of the invention a layered three-dimensional structurehaving a minimum feature size, the layered three-dimensional structureincludes: a first element; and a second element positioned adjacent tothe first element to define a third element positioned between the firstelement and the second element, wherein the third element is sized lessthan the minimum feature size.

In a second aspect of the invention a layered three-dimensionalstructure having a minimum feature size, the layered three-dimensionalstructure includes: a first layer defining a first opening, wherein thefirst opening is at least as large as the minimum feature size; and asecond layer positioned adjacent to the first layer, wherein the secondlayer defines a second opening at least as large as the minimum featuresize, wherein the second opening is positioned adjacent the firstopening to define a third opening between the first opening and thesecond opening, and wherein the third opening is capable of being sizedless than the minimum feature size.

In a third aspect of the invention a layered three-dimensional structurehaving a minimum feature size, the layered three-dimensional structureincludes: a first layer having a frame structure defining an array offirst openings, wherein each first opening is at least as large as theminimum feature size; and a second layer having a frame structuredefining an array of second openings, wherein each second opening is atleast as large as the minimum feature size, wherein the second layer ispositioned at least adjacent to the first layer, wherein the array ofsecond openings is positioned adjacent the array of first openings todefine an array of third openings between the array of first openingsand the array of second openings, and wherein each third opening iscapable of being sized less than the minimum feature size.

Further aspects of the invention will be understood by those of skill inthe art upon reviewing the teachings herein. Other aspects of theinvention may, for example, involve various combinations of the abovenoted aspects of the invention or combinations of one or more of theabove noted aspects with one or more features found in one or moreembodiments set forth herein. Other aspects of the invention may involveapparatus that can be used in implementing one or more of the abovemethod aspects of the invention. Other aspects of the invention mayprovide other configurations, structures, functional relationships, andprocesses that have not been specifically set forth above but which areexplicitly set forth herein below or are inherent or readilyascertainable by those of skill in the art upon review of the teachingsset forth herein.

Embodiments of the invention includes embodiments of devices (orstructures) and fabrication methods for producing them where thethree-dimensional device or structure includes elements (e.g. solidregions) which have dimensions smaller than a first minimum feature sizeand/or have spacings, voids, openings, gaps (e.g. hollow or emptyregions) located between elements, where the spacings are smaller than asecond minimum feature size where the first and second minimum featuresizes may be the same or different and where the minimum feature sizesrepresent lower limits at which formation of elements and/or spacings,respectively, can be formed. Reliable formation refers to the ability toaccurately form or produce a given geometry of an element, or of thespacing between elements, using a given formation process, with aminimum acceptable yield. The minimum acceptable yield may depend on anumber of factors including: (1) number of features present per layer,(2) numbers of layers, (3) the criticality of the successful formationof each feature, (4) the number and severity of other factors effectingoverall yield, and (5) the desired or required overall yield for thestructures or devices themselves. In some circumstances, the minimumsize may be determined by a yield requirement per feature which is aslow as 70%, 60%, or even 50%. While in other circumstances the yieldrequirement per feature may be as high as 90%, 95%, 99%, or even higher.In some circumstances (e.g. in producing a filter element) the failureto produce a certain number of desired features (e.g. 20-40% failure maybe acceptable while in an electrostatic actuator the failure to producea single small space between two relatively moveable electrodes mayresult in failure of the entire device.

In some embodiments, the determining factor for minimum feature size isbeing able to successfully pattern a masking material (e.g. photoresist)such that small elements are not inadvertently removed or delaminatedfrom a substrate. In this regard, an element of masking material may beconsidered to be larger than a minimum feature size if it is can bedivided into rectangular elements each having a width and length largerthan the minimum feature size. Though any exposed corners of suchfeature will have dimensions (e.g. radius of curvature) smaller than theminimum feature size, the elements as a whole are larger than theminimum feature size. In fact, in some circumstances elements havefeatures with angles of solid greater than 60 degrees and even 45degrees which are connected to masses larger than the minimum featuresize may be considered as being larger than the minimum feature size.

Device and structures and methods for forming devices or structures ofsome embodiments of the invention will result in spacings or elementshaving dimensions at or larger than a minimum feature size while thespacings as measured between two or more consecutive layers will be lessthan the minimum feature size.

In some embodiments the elements may have some structural features(corners of rectangular elements, corners having extended regionsforming angles greater than 60 degrees or even 45 degrees) smaller thanthe minimum feature size or some openings (corners of rectangularindentations into elements, corners of indentations having extendedregions forming angles greater than 60 degrees or even 45 degrees)smaller than the minimum feature size within a given layer.

In some embodiments of the invention, the apparatus or devices formedembody a layered three-dimensional structure which has a minimum featuresize for each layer. The device includes a first element and a secondelement, where the second element is positioned adjacent the firstelement to define a third element there between. Unlike the first andsecond elements, the third element is capable of being sized less thanthe minimum feature size.

With the third element sized less than the minimum feature size,depending on the embodiment, the spacing between the first and secondelements can be less than the minimum feature size. This allows theperformance and efficiency of the device to be significantly increased.In embodiments where electrical differentials are applied between thefirst and second elements (e.g. actuators), to generate forces therebetween, the closer the positioning, the greater the force produced orless voltage that is needed. Increasing the force applied to an elementof the device can result in a greater operational capacity with devicessuch as actuators. Decreasing the voltage needed, provides a reductionin the potential for adverse effects, such as shorting, arcing, chargeaccumulation and/or structural damage from melting or burning outstructure. In embodiments where a flow is controlled (restricted)between the first and second elements (e.g. filters), the performance ofthe device is increased by allowing restriction of particles sized lessthan the minimum feature size.

In some embodiments, the device is an actuator (e.g. a vertical orhorizontal comb actuator) or a micro-filter. With an actuator the firstand second elements can be openings defined in adjacent layers orstructures such as electrodes. Such structures can be fixed and/movableto provide an actuation function. The third element of the actuator istypically an opening or gap separating the structures such that they canmove relative to each other without contact. To provide such movement,the first and second elements can be electrically conductive, such thatthe actuator is capable of applying an electrical differential betweenthe first and second elements to create an electrostatic force.

With a micro-filter, the first and second elements can be eitheropenings (pores, gaps, etc.) defined in adjacent layers or thestructures defining openings. The third element of a micro-filter may bean opening, such as a pore for allow the passage of a substance such asa gas, liquid or particles.

Structural embodiments of the first and second elements can made of avariety of materials, such as for example gold, silver, nickel and/orcopper. In certain embodiments the structures are made of nickel. Thelayers of the layered structures can vary in thickness, typicallyranging between 1 μm and 50 μm, and in some cases, may be thinner orthicker.

In other embodiments, the three-dimensional structure has a firstelement abutting a first void, and a second element abutting a secondvoid. The first element and the first void are positioned along a firstplane and the second element and the second void are positioned along asecond plane. The first and second planes are parallel and adjacent. Thesecond void is positioned to abut (e.g. in communication with) the firstvoid. The second element is spaced from the first element a distancethat is less than the minimum feature size of either element. Theseembodiments can also be employed in devices such as actuators andmicro-filters. With applications such as actuators, the elements may bemovable, such that the first and/or the second elements may move intothe second and/or first voids, respectfully.

Other embodiments of the invention include a layered three-dimensionalstructure having a minimum feature size, the device including a firstlayer defining a first opening and a second layer defining a secondopening. The second layer is positioned adjacent or in contact (upon)the first layer and the second opening is adjacent or abutting the firstopening. Since the first and second openings are positioned withinlayers, they each are sized at least as large as the minimum featuresize. Between the second opening and the first opening is defined athird opening, which because it is located between the layers, iscapable of being sized less than the minimum feature size. A typicalapplication of these embodiments is as a micro-filter as the openingscan function as pores in the filter.

Embodiments of the invention also includes methods of fabricating alayered three-dimensional structure (e.g. substrate). In at least oneembodiment, a method for fabricating a three-dimensional structurehaving a minimum feature size includes the processes of providing adeposition structure, depositing at least a portion of a first layerhaving a first gap in at least a first material onto the depositionstructure, depositing at least a portion of a second layer having asecond gap in a second material onto the first layer to form a layeredstructure and releasing the layered structure from a third material. Thesecond layer has a second gap that is positioned to overlap the firstgap to define a third gap between the first and second layers. Since thethird gap is positioned at the overlap of the first and second gaps, itis capable of being sized less than the minimum feature size. Incontrast, with the first and second gaps being positioned within theirrespective layers, are sized at least as large as the minimum featuresize.

The deposition structure provided by the method can be a substrate or alayered structural, made of materials such as silicon, metal, glass orplastic. The deposition structure can include a sacrificial material, sothat after release, a space can be created adjacent (under) the device.This space can be used for structure movement (for actuators), and/orallowing a fluid flow (for filters). The layer deposition processes caninclude the operations of applying a patterned mask defining depositionregions at least adjacent to the deposition structure, depositing thelayer material, and removing the patterned mask. The application of thepatterned mask can be by a variety of processes.

In other embodiments of the fabrication method the processes includeproviding a deposition structure, depositing a first set of layercomprising at least one layer having a first structural region having atleast first and second opposing ends that abut a first sacrificialregion, depositing a second set of layers comprising at least one layerhaving a second structural region forming a layered structure, andreleasing the layered structure from any material occupying thesacrificial region. The second structural region is deposited over thefirst opposing end and extends from the first opposing end over part ofthe first sacrificial region wherein an end portion of the secondstructural region over the sacrificial region is spaced from the secondopposing end by a distance less than the minimum feature size. Thesecond set of layers can also include a second sacrificial region whichis positioned to abut the second structural region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C schematically depict side views of various stages of a CCmask plating process, while FIGS. 1D-G schematically depict a side viewsof various stages of a CC mask plating process using a different type ofCC mask.

FIGS. 2A-2F schematically depict side views of various stages of anelectrochemical fabrication process as applied to the formation of aparticular structure where a sacrificial material is selectivelydeposited while a structural material is blanket deposited.

FIGS. 3A-3C schematically depict side views of various example apparatussubassemblies that may be used in manually implementing theelectrochemical fabrication method depicted in FIGS. 2A-2F.

FIGS. 4A-4I schematically depict the formation of a first layer of astructure using adhered mask plating where the blanket deposition of asecond material overlays both the openings between deposition locationsof a first material and the first material itself.

FIG. 5A schematically depicts a top view of a layered actuator and FIG.5B schematically depicts a side view of the layered actuator.

FIG. 6 schematically depicts a top view of a filter structure having aseries of openings.

FIGS. 7A-7F schematically depict side views of various stages offabrication of a layered structure in accordance with at least oneembodiment of the invention.

FIG. 8 is a flowchart of a method of least one embodiment of theinvention.

FIG. 9 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 10 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 11 provides a flowchart of a method of least one embodiment of theinvention.

FIG. 12 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 13 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 14 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 15 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 16 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 17 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 18 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 19 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 20 schematically depicts a perspective view of a layered structurein accordance with at least one embodiment of the invention.

FIG. 21A schematically depicts a side view of FIG. 20 and FIG. 21Bschematically depicts a top view of FIG. 20 in accordance with at leastone embodiment of the invention.

FIG. 22 schematically depicts a top view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 23 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 24 schematically depicts a top view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 25A schematically depicts a top view of a layered structure andFIG. 25 b schematically depicts a side view of the layered structure inaccordance with at least one embodiment of the invention.

FIGS. 26A and 26B schematically depict top views of a layered structurein accordance with at least one embodiment of the invention.

FIG. 27 provides a flowchart a method of least one embodiment of theinvention.

FIGS. 28A-28E schematically depict side views of various stages offabrication of a layered structure in accordance with at least oneembodiment of the invention.

FIG. 29A-29C schematically depict top views of two layers of a layeredstructure in accordance with at least one embodiment of the invention.

FIGS. 30A-30C schematically depict side views of various stages offabrication of a layered structure in accordance with at least oneembodiment of the invention.

FIG. 31 provides a flow chart of a method of least one embodiment of theinvention.

FIG. 32A schematically depicts a side view of a layered structure andFIG. 32 b schematically depicts a top view of the layered structure inaccordance with at least one embodiment of the invention.

FIG. 33 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

FIG. 34 schematically depicts a side view of a layered structure inaccordance with at least one embodiment of the invention.

DETAILED DESCRIPTION

FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of one form ofelectrochemical fabrication that are known. Other electrochemicalfabrication techniques are set forth in the '630 patent referencedabove, in the various previously incorporated publications, in variousother patents and patent applications incorporated herein by reference,still others may be derived from combinations of various approachesdescribed in these publications, patents, and applications, or areotherwise known or ascertainable by those of skill in the art from theteachings set forth herein. All of these techniques may be combined withthose of the various embodiments of various aspects of the invention toyield enhanced embodiments. Still other embodiments may be derived fromcombinations of the various embodiments explicitly set forth herein.

FIGS. 4A-4I illustrate various stages in the formation of a single layerof a multi-layer fabrication process where a second metal is depositedon a first metal as well as in openings in the first metal where itsdeposition forms part of the layer. In FIG. 4A, a side view of asubstrate 82 is shown, onto which patternable photoresist 84 is cast asshown in FIG. 4B. In FIG. 4C, a pattern of resist is shown that resultsfrom the curing, exposing, and developing of the resist. The patterningof the photoresist 84 results in openings or apertures 92(a)-92(c)extending from a surface 86 of the photoresist through the thickness ofthe photoresist to surface 88 of the substrate 82. In FIG. 4D, a metal94 (e.g. nickel) is shown as having been electroplated into the openings92(a)-92(c). In FIG. 4E, the photoresist has been removed (i.e.chemically stripped) from the substrate to expose regions of thesubstrate 82 which are not covered with the first metal 94. In FIG. 4F,a second metal 96 (e.g., silver) is shown as having been blanketelectroplated over the entire exposed portions of the substrate 82(which is conductive) and over the first metal 94 (which is alsoconductive). FIG. 4G depicts the completed first layer of the structurewhich has resulted from the planarization of the first and second metalsdown to a height that exposes the first metal and sets a thickness forthe first layer. In FIG. 4H the result of repeating the process stepsshown in FIGS. 4B-4G several times to form a multi-layer structure areshown where each layer consists of two materials. For most applications,one of these materials is removed as shown in FIG. 4I to yield a desired3-D structure 98 (e.g. component or device).

Various embodiments of various aspects of the invention are directed toformation of three-dimensional structures from materials some of whichare to be electrodeposited. Some of these structures may be formed forma single layer of one or more deposited materials while others areformed from a plurality of layers of deposited materials (e.g. 2 or morelayers, more preferably five or more layers, and most preferably ten ormore layers). In some embodiments structures having features positionedwith micron level precision and minimum features size on the order oftens of microns are to be formed. In other embodiments structures withless precise feature placement and/or larger minimum features may beformed. In still other embodiments, higher precision and smaller minimumfeature sizes may be desirable.

Various embodiments of the invention may perform selective patterningoperations using conformable contact masks and masking operations,proximity masks and masking operations (i.e. operations that use masksthat at least partially selectively shield a substrate by theirproximity to the substrate even if contact is not made), non-conformablemasks and masking operations (i.e. masks and operations based on maskswhose contact surfaces are not significantly conformable), and/oradhered masks and masking operations (masks and operations that usemasks that are adhered to a substrate onto which selective deposition oretching is to occur as opposed to only being contacted to it). Adheredmask may be formed in a number of ways including (1) by application of aphotoresist, selective exposure of the photoresist, and then developmentof the photoresist, (2) selective transfer of pre-patterned maskingmaterial, and/or (3) direct formation of masks from computer controlleddepositions of material.

In this application, minimum feature size (MFS) associated with amulti-layer micro-scale or meso-scale device or fabrication processrepresents a physical limit of how small features of the device are thatcan be reliably formed or defined by the process. In other words, theMFS represents the minimum reliably formed spacing between solidfeatures of a structure on a given layer or the minimum reliably formedwidth 6 f such solid features of a structure on a given layer. The MFSfor minimum spacing between solid features may be termed the minimum gapsize (MGS) while the MFS for the minimum width solid features may betermed the minimum solid size (MSS). In some processes the MFS resultsfrom a limited size of masking material features that may be reliablyformed (i.e. minimum feature sizes of openings in the masking materialor minimum feature sizes of solid portions of the masking material. Insome embodiments, the minimum feature size may be a function of thethickness of the mask or the layers of material that will be depositedinto the mask. Depending on whether a mask is used to depositsacrificial material or structural material, minimum features associatedwith a mask may correspond to minimum features sizes of a layer of astructure that will be formed with the mask or they may representreversed features relative to the mask. Any structure formed using amask, will have elements or features which are at least as large as theminimum size of the features of the mask. Therefore, the MFS of the maskplaces a specific limit on how small a structural element (i.e. solidportion) can be and/or how close structural portions (i.e. solidportions) can be spaced to one another (i.e. how big gaps betweenstructural portions must be).

One example class of structures or devices (i.e. one application) mayinvolve an electrostatic actuator where a desired feature to minimizemay be a separation between the a fixed element and the movable element(e.g. teeth of a comb drive or other electrostatic actuator. Anotherexample class of structures or devices may involve a screen or filterwhere the feature to be minimized is the openings or passages (e.g.pores) in the structure. An additional example may be the width ofelements that are intended to provide desired compliance or resiliencewhen deflected in a given direction.

Decreasing the size of obtainable features on a device may allow anincrease in the obtainable performance. Decreasing the feature size inan actuator allows the separation between structures to be reduced andmay result in higher driving forces for a given supply voltage.Likewise, with a filter, a decrease in the size of the openings or inthe size of the solid elements between openings in the structure allowssmaller particles to be filtered and/or more filter openings to beformed in a given area or volume.

One example of an actuator is shown in FIGS. 5A and 5B. The actuator 500includes a pair first elements (e.g. fixed elements) 520 on either sideof a center slider or second element 540. Both the first element 520 andsecond element 540 are made from a plurality of stacked layers (e.g.horizontal layers 522 as shown in FIG. 5B). A series of layers 522 ofthe first element 520 include vertically aligned ends 524. The secondelement 540 has a series of layers 542 with vertically aligned ends 544positioned opposite the ends 524. Separating the first and secondelements are gaps 560. The gaps have a width or separation distance A5.The slider 540 is configured to allow movement in an X-direction (whichis vertical as shown in the side view of FIG. 5B) upon the applicationof a force between the set of first elements 520 and is configured torestrict movement in the two perpendicular directions. The movement inthe X-direction may be constrained by spring elements (not shown) havinga desired compliance in the X-direction and such spring elements mayoffer limited or essentially no compliance in one or both of the twoother perpendicular directions as well as in rotational directions.Examples of actuators and other elements that may benefit from theteachings found herein are described in U.S. patent application Ser. No.10/313,795, filed Dec. 6, 2002 by Bang et al. which is incorporatedherein by reference as if set forth in full herein.

The actuation force can be an electrostatic force created by an electricpotential applied between the elements 520 and 540. The amount of forcecreated for a given voltage, or the amount of voltage needed to producea given force, is directly dependent on the distance separating theelements. The closer the elements are placed, the less voltage neededfor a given displacement and/or the greater force which is produced. Asa result the efficiency of the actuator can be improved my minimizingthe distance of separation.

However, as noted, the minimum separation A5 between the first element520 and the second element 540 on a given layer is limited by the MFS ofthe build process (i.e. the MGS) which sets a minimum gap betweenstructural elements. As a result, the maximum performance of theactuator 500 is limited as a function of the MGS.

An example of a filter is illustrated with the aid of FIG. 6, whereinthe filter 600 includes a structure 610 that defines a series ofopenings 612 spaced across the structure 610. The dimension of thesquare openings 612 is a width A6. This dimension is limited by the MGSof the process. That is, the MGS determines the how fine a filter canbe. Furthermore, the minimum width of structure between openings 612 isset by the MSS which may be equal to the MGS or different from it. Thesmaller the MSS, the more openings that can be inserted into a givenarea or volume and the more efficient the filter can be.

A need exists for improved devices, and methods for fabricating suchdevices, which is capable of providing increased performance by reducingthe width of structural elements and/or the size of openings betweenstructural elements, to lengths less than the MSS and MGS respectively.

Some embodiments of the invention include structures (e.g. devices,components, apparatus, and the like) and methods of fabrication thereof,having features and elements sized and/or spaced at lengths which areless than the minimum feature size (MFS) or the minimum structure size(MSS) and/or minimum gap size (MGS) if they are not equal. The abilityto construct and shape at less than the MFS allows for the fabricationof structures with performance and capabilities not achievable in heretobefore. As set forth in greater detail herein, examples of such devicesinclude comb-drive actuators and micro-filters.

Obtaining elements sized and spaced less than the MGS can be achievedwith a variety of structures in different ways. One such manner is toutilize selective positioning and configuring of different layers (whichthemselves each remain limited by the MGS) of a device, to form alayered structure which has elements sized and/or spaced at distancesless than the MGS. The positioning and configuring of layers can involvethe shifting or staggering of openings or spaces defined in separatelayers such that a resulting gap is formed between elements and has awidth which is less than the MGS. Also, the layers can be arranged sothat the openings or spaces in adjacent layers are connected (e.g.overlapped) to define passages in the structure that have regions sizedless than the MFS.

In some embodiments where the MGS may upon initial consideration besmaller than the MSS, may be possible to reverse the these results byreversing the deposition order of a sacrificial material and thestructural material. This is most particularly the case when the sourceof the MGS and MSS is related to minimum mask features. As such, the MSSmay be made to be smaller than the MGS and negative effects associatedwith an excessively large MGS may be addressed using variouslayer-by-layer offsetting techniques described herein and as suchminimum overall feature and gap size may be obtained.

An advantage provided by certain embodiments of the invention is that byreducing element size and spacing to less than the MFS, the performanceand efficiency of the device can be significantly increased. As notedabove, in embodiments where electrical differentials are applied betweenelements, to generate forces to actuate structures, the closer thepositioning, the greater the force produced or less voltage that isneeded. That is, by reducing the spacing, a greater force can begenerated for a given voltage and/or less voltage differential is neededto achieve a desired force. Increasing the force applied to an elementof the device can result in a greater operational capacity with devicessuch as actuators. Decreasing the voltage needed, provides a reductionin the potential for adverse effects, such as shorting, arcing, chargeaccumulation and/or structural damage from melting or burning outstructure.

Likewise, in some embodiments of the invention, reducing the size offeatures to less than the MFS, can provide improve performance. Examplesinclude filter structures which can be made finer by reducing the sizeof the openings (e.g. pores) across the filter. The increased filtrationresults from the capability to prevent passage of particles smaller thanthose restricted by the prior devices. That is, some embodiments of theinvention allow the separation of a greater range of particle sizes fromthe subject solution (e.g. gases, fluids) than previously obtainable.

The methods of the invention include the fabrication of devices havingat least some features (i.e. gaps or elements) sized less than the MFS(i.e. MGS and MSS). These methods can include electro-depositionprocesses or electroless deposition processes (e.g. electrochemicalfabrication process) to build up structures through the deposition of aseries of layers. The layers deposited having features arranged (e.g. bysizing and positioning) to allow the construction of intra-layer layerfeatures less than that dictated by the MGS. For example, to fabricate adevice (e.g. an actuator) having structures separated by a gap sizedless than the MGS, the method can include depositing a series of layerswith alternating positions of openings or spaces in each layer. Sincethe features on any given layer cannot be sized less than the MFS, theopenings are at least the size of the MFS on each layer. However, theintra-layer staggering of the openings allows portions (e.g. alternatelayer ends) of the structures to be positioned less than the MFS apart.Similar fabrication methods can be used to position openings of MGS sizeor larger, to connect (e.g. overlap) between layers to form passagesthat have a dimension smaller than the MGS. These methods are furtherdetailed herein.

Apparatus Embodiments

The apparatus of the invention can be a layered three-dimensionalstructure with elements which are sized less than the minimum featuresize of the layers. The three-dimensional structure includes a firstelement and a second element, where the second element is positionedadjacent the first element to define a third element there between.Since the first and second elements are defined by layers of the device,they must be at least as large as the minimum feature size. In contrast,the third element, being defined by the first and second elements, iscapable of being sized less than the minimum feature size. The first andsecond elements be a variety of structures, such as single materiallayers or layered structural components, also they can be definedfeatures such as openings, gaps and voids. Likewise, the third elementcan be a multitude of different features including an opening, gap orvoid.

An embodiment of the apparatus of the invention having two layers withoverlapping gaps is shown in FIG. 7A. By offsetting the gaps in adjacentlayers, a smaller overlap or defined gap can be created at theintersection of the layers and the overlap of the layer gaps. As aresult, the size of this defined gap is based only on the amount ofoffset and is not limited by the MFS of either layer, allowing thedefined gap to potentially be sized smaller than the MFS. As furtherdetailed herein, this arrangement of the layers and gaps can be employedin a variety of structures, including actuators and filters.

FIG. 7A shows the device 700 a which includes a first structure 720, asecond structure 740 and a gap 760 separating them. The first structure720 includes a set of layers 722 with a first or base layer 726 and asecond or top layer 730. The base layer 726 has an end 728 and the toplayer has an end 732. The second structure 740 includes a series oflayers 742, with a first or base layer 746 and a second or top layer750. The base layer 746 has an end 748 and the top layer has an end 752.

The first layers 726 and 746 are commonly aligned with a gap separatingthem. Depending on the specific fabrication method (further detailedherein), the first layers can be constructed in a common layer ofmaterial with the gap defined therein. Likewise, the second layers 730and 750 are commonly aligned and are capable of having been formed fromthe same layer of material.

The layers 722 and 742 can be of any of a variety of suitable material,some examples including gold, silver, nickel, copper, and the like. Insome embodiments the material used for the layers is a nickel. Thelayers 722 and 742 can vary in a range of possible thickness, forexample in some embodiments, layers 722 and 742 have a thickness in therange of 1 μm to 20 μm. In particular embodiments the thickness of thelayers is about 6 μm. The listed materials and layer thickness can beapplied to other embodiments of the invention set forth herein.

The gap 760 includes a sub-gap 762, set between the ends 728 and 748,and a sub-gap 764, between the ends 732 and 752. The sub-gaps 762 and764 can vary in size, depending on the embodiment, as shown they eachhave a width of the distance A7. While the width A7 can be greater thanthe MFS, the minimum obtainable size of the width A7 is the MFS. Thesub-gaps 762 and 764 are positioned to overlap, forming an overlap,defined or third gap 766. The overlap gap A7 has a width of the distanceB7, which is capable of being sized less than the MFS.

The value of the MFS will vary depending on the particular fabricationmethods employed (as described further herein). For example, with anINSTANT MASK™ (detailed herein), the MFS is related to the minimum sizeof features in the mask itself. In some embodiments, the MFS for theINSTANT MASK™ process is 20 μm to 40 μm.

The device 700 a can be used in a variety of applications, includingactuator or filter structures. For example, with the first structure 720and the second structure 740 separated from each other (no connectingstructure shown in FIG. 7A), and with either or both the structures 720and 740 configured to be movable, the device 700 a can function, uponthe application of a electrical differential between the structures, asan actuator. With the first and/or second structure moving verticallytowards each other (e.g. a vertical comb actuator), the ends 732 and 748will move to be separate by only the distance B7, as the ends 732 and748 align with each other. This allows the performance of such anactuator to be increased as the separation between the structures 720and 740 is reduced from the MFS limited distance A7 to the shorterdistance B7. As described herein, by increasing the number of layers, asthe actuator moves, the number layers which can be positioned within adistance less than the MFS can also be increased, for an associatedincrease in performance. Also as described herein, such actuators can beconfigured to move in horizontal and depth-wise directions.

A filter is another example of an application of the device 700. Thiscan be achieved by flowing a substance (such as a gas, liquid, a seriesof particles, etc.), through the device such that the gap 760 becomes aflow passage. Since the overlap gap 766 has the minimum dimension of thepassage (e.g. width B7), it will determine the degree of filtration ofthe device 700. Since embodiments of the invention allow the forming ofopenings sized less than the MFS, the performance of such a filter canbe increased by allowing it to prevent passage of a greater range ofparticle sizes. That is, the amount of filtration can be increased byrestriction passage of even smaller particles.

Fabrication Method Embodiments

Devices such as the device 700 a can be fabricated by a variety ofdifferent embodiments of the method of the invention. In general, thesemethods include depositing a first layer with a first gap and then overthe first layer depositing a second layer with a second gap. The secondgap is positioned to overlap the first gap such that a third gap isdefined between (at the intersection of) the first layer and the secondlayer. This provides the advantage that, unlike the first and secondgaps which must be sized at least as large as the MFS, the third gap isonly dependent on the amount of overlap of the other two openings.

As shown in FIG. 8, in at least one embodiment the method is a methodfor fabricating a thin film (e.g. MEMS) device having a minimum featuresize 800, which includes the processes of providing a depositionstructure 810, depositing a first layer having a first gap, onto thedeposition structure 820, depositing a second layer having a second gaponto the first layer to form a layered structure, wherein the secondlayer has a second gap overlapping the first gap to define a third gap830, and releasing the layered structure 840. As will be detailedherein, structures obtainable by operation of the method 800 can be of avariety of different embodiments, examples of which are shown herein.

During the process providing a deposition structure 810, a structurewith a suitable surface for the later deposition of the first layer isobtained. The deposition structure can be any of several different typesof structures including, a substrate and a layered or formed structuralor sacrificial structure. With the deposition structure being asubstrate any of a variety of suitable materials, formable to have asurface smooth enough to allow for the deposition of the sacrificialmaterial, can be used. Such suitable materials can include silicon, ametal (e.g. nickel, copper, silver, gold, etc.), glass or plastic.

In certain embodiments where the final device needs to be capable ofbeing released from the substrate, where elements or structures of thedevice need space below the first layer to operate (e.g. actuators), orwhere a fluid or gas is to flow through the an opening in the device(e.g. filters), at least a portion of deposition structure can be of asacrificial material to space the device from a substrate or otherstructure. In such embodiments, the deposition surface is positionedupon the sacrificial layers. By later removing the sacrificial layers,an open space will be created to release the device, allow movement ofdevice, or create a pathway for a flow of a fluid or gas.

In such embodiments, the process 810 can include the steps of providinga substrate, depositing sacrificial material upon the substrate, andforming a deposition surface on the sacrificial material. Thesacrificial material can be one or more layers. Layers of sacrificialmaterial can vary in thickness, in some embodiments the layers arebetween 4 μm and 20 μm thick. The sacrificial material can be any of avariety of suitable materials (e.g. gold, silver, nickel, copper, andthe like), with some embodiments having sacrificial material as asilver. Deposition of the sacrificial material can be any of a varietyof methods. Likewise, the deposition surface provided can be formedthrough any of a variety of methods well known in the art includingetching (wet or dry), milling, lapping, molding, extrusion and the like.

In some embodiments, the process 810 can also include applying a seedlayer on the structure in order to facilitate later layer deposition.For instance, if the material of the structure used is not sufficientlyconductive (e.g. plastic or glass) to allow electrodeposition techniquesto be employed for layer deposition, then a seed layer of conductivematerial can be used.

Operation of the process of providing a deposition surface 810 on asacrificial layer can result in the embodiment of a device 700 b shownin FIG. 7B. A device 700 b includes a substrate 702, a layering ofsacrificial material 704 and a deposition surface 706.

Another process of the method 800 is depositing a first layer having afirst gap onto the deposition structure 820, as shown in FIG. 9. Thisprocess 820 can further include the steps of depositing a first layer ofmaterial with a gap defined therein, depositing a sacrificial materialto provide a continuous layer, and forming a deposition surface.

FIG. 7C sets forth an embodiment of a structure formable by theoperations of the process 1720. The step of depositing a first layer canprovide the layer 708 deposited over the deposition surface 706. Thefirst layer 708 has the structure 710 with a gap 712. The gap 712 has awidth of A7.

The material of the first layer 708 can be deposited to a thicknessgreater that the desired thickness of the first layer 708 as anyadditional material can be removed during the step of forming adeposition surface. In this embodiment the first layer 708 is astructural material. The specific material used for the structuralmaterial can vary (including gold, silver, nickel, copper, and thelike), in some embodiments the material is a nickel.

A variety of processes can be used to carry out the deposition of thematerial of the first layer 708. In some embodiments, the depositionprocess generally includes, providing a pattern mask defining thedeposition regions, depositing the first material, and removing themask.

The step of providing a mask can include the use of a variety ofdifferent processes using different type of masks and applications. Somesuitable masking techniques include use of a preformed mask (e.g. a CCmask) and some of a mask formed during the process on the depositionsurface (e.g. an adhered mask).

One type of suitable preformed mask is an INSTANT MASK™ (detailedabove), which can include a mask-on-anode (MOA) process and/or ananodeless instant mask process. In turn, the mask-on-anode process canemploy a variety of masking approaches, such as, conformable contactmasking, contact masking and proximity masking. A detailed descriptionof these processes and associated structures are detailed above.

While specific applications of mask-on-anode processes can vary,typically such a process involves positioning a patterned non-conductive(insulating) mask on or over an anode. In most cases, the mask and anodeare abutting substantially planar structures which allow them to bepositioned at least adjacent to the planar surface on which layerdeposition will occur. An example of such a configuration is shown inFIG. 1A, where the mask (insulator) 10 is attached to anode 12 andpositioned near the substrate 6.

The anode is of an electrically conductive material which during theelectro-deposition process (e.g. electrochemical fabrication) is asource for the deposition material. Also, the anode can function toprovide structural support for the mask. The mask is patterned to definethe locations at which the deposition will, and will not, occur. Thatis, since the mask is non-conductive (e.g. a dielectric material), andthe deposition process is performed in a conductive medium (e.g. anelectrolyte solution), the areas of the deposition surface left exposedby the mask will receive deposited material. An example of suchdeposition is shown in FIG. 1B, where material 22 is selectivelydeposited the substrate 6 by electrodepositing material throughapertures 26 a and 26 b in the insulator 10.

A conformable contact mask can be used in the mask-on-anode process. Theconformable contact mask (CC mask) is deformable so that when pressedinto contact with a non-uniform deposition surface, the mask can deformso as to contact all portions (high and low points) of the surface. Thisprevents gaps from forming between the mask and surface, which mayotherwise occur with a non-deformable mask. Such gaps are to be avoidedas they can allow material to be deposited at undesired locations.Material being deposited at these gaps or other such undesired locationsis typically referred to as flashing. The CC mask can be a silicone (orsimilar polymer) to provide deformation and non-conductive properties.The CC mask can be mounted to a substantially rigid or flexible anode,or other support structure, as set forth in detail herein. A detaileddiscussion of the use and configuration of conformable contact masks isprovided above and as shown in FIGS. 1A-1G, 2A-2E and 3A-3C.

Other masks include contact masks and proximity masks. While a contactmask is configured to directly contact the deposition surface duringdeposition, unlike a CC mask, a contact mask can be substantially rigid.A contact mask can be employed in situations where there is limited, orno, potential for gaps or voids to exist between the mask and thedeposition surface. That is, when the mask and the deposition surfacefit together close enough to sufficiently prevent flashing or otherundesired material deposition, then a contact mask can be used. In somecases contact masks are mounted on flexible anodes, or other supportingstructures, to allow the mask/anode element to conform to variations inthe deposition surface.

With proximity masking the mask is kept from direct contact with thedeposition surface. Depending on the embodiment, the distance betweenthe mask and the deposition surface can be minimized to limit anydeposition in undesired areas (e.g. flashing). Because a proximity maskis not in direct contact with the deposition surface, removing it awayfrom the deposition surface is facilitated. A proximity mask providesthe benefit of reducing the potential for damage from removal of themask from the deposition surface, increasing the usable life of themask.

As with CC masks, contact and proximity masks typically are made ofnon-conducting material patterned to allow selective deposition on thedeposition surface.

In other applications, the mask can be positioned so that it is notmounted directly to the anode. Instead, the mask can be mounted on asupporting structure remote from the anode. Examples of this type ofmask include an Anodeless INSTANT MASK™ (AIM) and an anodelessconformable contact (ACC) mask. A description of such embodiments is setforth in detail above and in FIGS. 1D-1F. Wherein the mask 8′ ispositioned on a structure 20′ and is separated a distance from the anode12′.

A benefit from employing a remote anode is that the degradation of theanode caused during the electrodepositing from providing the depositionmaterial, does not affect the structural integrity of mask/supportelement. With the mask mounted directly to the anode, aselectrodeposition occurs, material is lost from the anode at pointsunder the mask. This under-cutting reduces the structural support forthe mask, increasing the potential for gaps to form between the mask andthe deposition surface, allowing for flashing to form, and reduces thelife of the mask in the process.

Another type of mask available is an adhered mask. Unlike mask-on-anodeand anodeless instant mask techniques (e.g. INSTANT MASK™, AIM, ACCprocesses), with adhered masking the mask is formed during thefabrication process, adhered directly to the deposition surface and isnot reusable after the layer deposition is completed. However, adheredmasks are similar to Instant Masks in that they are patterned to definestructures to be deposited. An adhered mask can be any of a variety ofmaterials including a photoresist.

An example of an adhered mask process is shown in FIGS. 4A-4I,illustrating various stages in the formation of a single layer of amulti-layer fabrication process. During the fabrication process shown, asecond material (e.g. a second metal) is deposited on a first material(e.g. a first metal), and in openings in the first material (patternedby the adhered mask) to form portions of what will become the depositedlayer. In FIG. 4A, a side view of a substrate 82 is shown, onto which apatternable photoresist 84 is cast as shown in FIG. 4B. In FIG. 4C, apattern of resist is shown that results from the curing, exposing, anddeveloping of the resist. The patterning of the photoresist 84 resultsin openings or apertures 92(a)-92©) extending from a surface 86 of thephotoresist through the thickness of the photoresist to a depositionsurface 88 of the substrate 82. In FIG. 4D, a first material 94 (e.g. ametal such as nickel) is shown as having been electroplated into theopenings 92(a)-92©). In FIG. 4E, the photoresist has been removed (i.e.chemically stripped) from the substrate to expose regions of thesubstrate 82 which are not covered with the first material 94. In FIG.4F, a second material 96 (e.g. a metal such as silver or copper) isshown as having been blanket electroplated over the entire exposedportions of the substrate 82 (which is conductive) and over the firstmaterial 94 (which is also conductive). FIG. 4G depicts the completedfirst layer 97 of the structure which has resulted from theplanarization of the first material 94 and second material 96 down to aheight that exposes the first material 94 and sets a thickness for thefirst layer 97. In FIG. 4H is shown the result of repeating the processsteps shown in FIGS. 4B-4G several times to form a multi-layer structure98, where each layer consists of two materials set in varying patterns.For most applications, one of these materials is removed as shown inFIG. 4I to yield a desired 3-D structure 99 (e.g. a component or adevice).

A method for forming microstructures using photoresist andelectrochemical fabrication techniques is taught in U.S. Pat. No.5,190,637 to Henry Guckel, entitled “Formation of Microstructures byMultiple Level Deep X-ray Lithography with Sacrificial Metal layers('637 patent). This patent teaches the formation of metal structurewherein, a first layer of a primary metal is electroplated onto anexposed plating base to fill a void in a photoresist, the photoresist isthen removed and a secondary metal is electroplated over the first layerand over the plating base. The exposed surface of the secondary metal isthen machined down to a height which exposes the first metal to producea flat uniform surface extending across the both the primary andsecondary metals. Formation of a second layer may then begin by applyinga photoresist layer over the first layer and then repeating the processused to produce the first layer. The process is then repeated until theentire structure is formed and the secondary metal is removed byetching. The photoresist is formed over the plating base or previouslayer by casting and the voids in the photoresist are formed by exposureof the photoresist through a patterned mask via X-rays or UV radiation.

For the deposition of the material of the first layer 708 onto thedeposition surface 706, as shown in FIG. 7C, any of the above describedmasks and masking techniques can be employed. That is, selectivedeposition of the first layer 708 can be performed by a variety waysincluding INSTANT MASK™, mask-on-anode (MOA) (e.g. conformable contactmasking, contact masking and proximity masking), anodeless instant mask(AIM), anodeless conformable contact (ACC) mask, and adhered maskprocesses. Likewise, methods detailed in the disclosures (e.g. the '630patent and the '637 patent) incorporated by reference herein, may beused.

The use of a mask to deposit the first layer 708 limits the minimumobtainable size of any feature or element defined on the layer 708 tothe minimum feature size (MFS) of particular the mask used. The specificdimension of the MFS is dependent on the type of mask and maskingtechnique used. The MFS is a direct function of smallest feature whichcan be defined during the fabrication of the mask itself. As a resultthe minimum dimensions of the gap 712 defined in the structure 700 c isthe MFS of the process used.

After application of a mask the material of the first layer 708 isdeposited onto the deposition surface 706, by any of a variety ofelectrodeposition methods including any of the electrochemicalfabrication method described here. Then the mask used is removed and, asdetailed above, the type of mask removal is dependent on the type ofmask used. For preformed masks, the mask is removed by physicallyseparating the mask from its position during deposition and away fromthe deposition surface. With adhered masks the removal is typically donewith a solvent, although etching or planarization may be employed.

Following the deposition of the structural material of the first layer708, and the mask removal, a sacrificial material can be deposited tofill the first gap 712.

Another step in the process of depositing a first layer having a firstgap 820 is the step of depositing a sacrificial material to provide acontinuous layer of material. The deposition of the sacrificial materialallows later shaping and sizing of the layer by covering any exposedportions of the deposition surface such that a continuous material layeris formed. That is, by filling all exposed areas and gaps with thesacrificial material, methods such as planarization, which need acontinuous material to achieve desired results, can be employed. Thesacrificial material also functions to provide support to the structureof the first layer during the later planarization process go to preventundesired deformation of the structure.

An embodiment of a structure 700 d, which is obtainable by operation ofthe sacrificial material deposition step, is shown in FIG. 7D. As can beseen, the gap 712, the structure 710 have been covered by a sacrificialmaterial 714.

The sacrificial material 714 can be deposited by any of a variety ofmethods including a blanket electrodeposition. During a blanketdeposition the sacrificial material 714 is deposited upon all exposed(conductive) areas of the entire structure 700 c. A mask is nottypically used since the deposition is not selective. However, in someembodiments, to protect the exposed sides (not shown) of the substrate702 from undesired material deposition, an insulating structure (notshown) is moved into position about the sides of the substrate 702.Typically, the insulating structure is ring shaped to match a cylindershaped substrate.

The blanket deposition can be achieved by electroplating from an anode(not shown), composed of the sacrificial material 714, through anappropriate plating solution (not shown), and to the cathode, which hereis the structure 700 c (or at least the exposed surface thereof).

It should be noted that in alternate embodiments of method the materialof the structure 710 can be a sacrificial material instead of astructural material, and likewise the sacrificial material 714 is astructural material.

The next step in the deposition process 820 is the step of forming adeposition surface. During this step the layer is sized and shaped byremoving the excess portions of the deposited layer material (e.g. thestructural and sacrificial material), to achieve a layer of a desiredthickness and surface.

Shown in FIG. 7E is an embodiment of a structure 700 e which can befabricated by this shaping step. The structure 700 e includes the layer708 with the structure 710 and gap 712, sized to a desired thickness. Bysizing the layer 708, the first base layer 726 and second base layer 746of the device 700 a (as shown in FIG. 7A) are formed. The layer 708 alsoincludes a deposition surface 715 for the later deposition of the secondlayer 716. The surface 715 is sufficiently smooth to allow deposition ofthe second layer 716.

The process of sizing and shaping the deposited material to achieve thestructure 700 e can be achieved by any of a variety of methods wellknown in the art including, etching (wet or dry), milling, lapping andthe like. One such method is planarizing by a lapping operation. Duringlapping, material is removed by moving an abrasive element over, orrelative to, the surface of the structure 700 d (shown in FIG. 5D),until a desired thickness of the layer and smoothness of the surface isachieved.

Another process of the method 800 is depositing a second layer having asecond gap onto the first layer to form a layered structure, wherein thesecond layer has a second gap overlapping the first gap to define athird gap 830. This process functions to define a gap or opening set atthe intersection of the first and second layers which is capable ofbeing sized less than the gaps set in either layer. Because the size(e.g. width) of the third gap is solely dependent on the positioning ofthe first and second gaps, it is not limited by any feature sizelimitations typically inherent in the manufacture of a layer ofmaterial. As noted herein, such a limitation is the MFS, which the thirdgap can be sized less than.

The deposition process 830 can be performed in a variety of ways. In oneperformance of the process 830 the second layer is deposited by theselective deposition steps of applying a mask, depositing the materialand removing the mask Any of a variety of described masks and maskingtechniques (e.g. INSTANT MASK™, MOA, AIM, ACC, methods detailed in the'630 patent and '637 patent disclosures), can be employed. Deposition ofthe material can be performed by any of a variety of electrodepositionmethods described herein. The mask is removed by a process appropriateto the type of mask used. Since this embodiment of the process lacks aforming (sizing and shaping) step, the thickness of the layer set whenthe material is deposited. Also, the upper surface (e.g. laterdeposition surface) of the second layer is formed by theelectrodeposition and not by a planarization or other forming process.

An embodiment of a structure 700 f that is obtainable by an embodimentof the deposition process 830 using only steps of selective depositionto form a second layer 716 is shown in FIG. 7F. As shown, the secondlayer 716 includes a second structure 718 defining a second gap 719. Thesecond gap 719 is positioned to overlap the first gap 714 to define athird gap 717. With the second layer 716 sized to the desired thicknessof the final structure, the second structure 718 includes the top layer730 and the top layer 750, separated by the sub-gap 764.

The deposition process 830 can include, in addition to the selectivedeposition step, the steps of depositing sacrificial material andforming the second layer. These steps are similar to those detailedherein as part of the deposition process 820 (above). Namely, thesacrificial material is deposited to fill the gap 719, by blanketdeposition or other methods and then the structure is formed by sizingand shaping through any of a variety of methods including planarization.

The next process in the fabrication method 800 is releasing thereleasing the layered structure 840. During this process the structuresdefined during the deposition of layers are released from the built upstructure by removing the sacrificial material. The sacrificial materialcan be removed by any of a variety of methods including using an etchingprocess. Useable etching processes include applying a chemical etchantwhich is sufficiently reactive with the sacrificial material to dissolveit. However, to maintain the desired structures during the etch, theetchant used should be substantially non-reactive with the structuralmaterial, or at least limited in its reaction to the structural materialto prevent, or properly limit, etching of the structural material.

FIG. 7A shows an embodiment of a structure 700 a which can be obtainedafter performing the releasing process 840. This is achieved by removingthe sacrificial material from the structure 700 f (as shown in FIG. 7F).The material removed includes the layers 704 and the sacrificialmaterial 714 in the gap 712. Depending on the embodiment of the process830, any sacrificial material deposited in gap 719 is also removed.

In an alternate embodiment, the method 800 can further include a processof moving the first structure or the second structure towards the otherstructure, or moving the first and second structures towards each otherto reduce the spacing between the structures. This additional process isapplicable to embodiments where the device is an actuator or othermoving structure. This process can be achieved by steps involving theapplication of a charge between the structures to create a force therebetween.

Actuator Embodiments

Shown in FIG. 9 is an embodiment of the invention which can have amovable structure and which is capable of functioning as an actuator.The device 900 has a first structure 920 and a second structure 940separated by a gap 960. Depending on the embodiment, one or both of thestructures is capable of moving and/or being actuated. In someembodiments, one structure is set in a fixed position, while the otherstructure is movable. The device 900 has a series of layers having gapsthat are offset from each other in a staggered arrangement to define aset of recessed and extended regions. This provides an advantage ofincreased performance by allowing the extended portions of the layers tobe positioned closer to each other than is possible with aligned gaps.

The device 900 can be a portion of an actuator such as a vertical combactuator. The structures 920 and 940 can be electrodes. The firststructure 920 may move in a vertical direction X1 and/or the secondstructure 940 may move in a vertical direction X2. One of the structures920 or 940 may be fixed in position by being mounted to any of a varietyof structures (not shown). With one or both movable structures 920 and940, movement can be achieved by applying a force between thestructures. One means of generating such a force is by applying avoltage differential between the structures.

The first structure 920 includes a series of layers 922. The layers 922include first recessed layers 926 and first extended layers 930. Therecessed layers 926 are positioned back from the rest of the structureand the extended layers 930 are positioned out towards the secondstructure 940. The recessed layers 926 have ends 928 and the extendedlayers 930 have ends 932.

Likewise, the second structure 940 includes a series of layers 942. Thelayers 942 include second extended layers 946 and second recessed layers950. The extended layers 946 are positioned out towards the firststructure 920 and the recessed layers 950 are positioned back from therest of the structure. The recessed layers 950 have ends 952 and theextended layers 946 have ends 948.

In the position of the device 900 as shown in FIG. 9, the gap 960includes a first sub-gap 962 and a second sub-gap 964. The first sub-gap962 and the second sub-gap 964 overlap to form a third sub-gap 966. Thefirst sub-gap 962 is positioned between the ends 928 and 948, and thesecond sub-gap 964 between the ends 932 and 952. The widths of thesub-gaps 962 and 964 are a distance A9, which is some embodiments is theMFS. In alternate embodiments to that shown in FIG. 9, the specifichorizontal positioning of the sub-gaps can vary along each aligned layer(e.g. positioned in part on either of the two structures). However, theminimum width of the sub-gaps, regardless of their specific positioningis the MFS.

Between the ends 932 of the first extended layers 930 and the ends 948of the second extended layers 946, the separation is a distance B9. Thisis the width of the third gap 966. The distance B9 is set by the aboutof overlap between the first sub-gap 962 and the second sub-gap 964. Assuch, the length of the distance B9 is independent of the widths A9 ofthe sub-gaps 962 and 964 and therefore of any limitation in the size ofthe sub-gaps, including the MFS. As a result, the separation B9 betweenthe first structure 920 and the second structure 940 is capable of beinga distance which is less than the MFS.

As the positions of the first structure 920 and the second structure 940move relative to one another, the size and shape of the gap 960 willchange, and the sub-gaps 962 and 964 will no longer be defined in thegap 960 as shown in FIG. 9. As the structures move the extended layers930 and 946 will align to provide a narrow sub-gap (with a width of B9)there between. However, at the same time the recessed layers 926 and 950will align to form an extended sub-gap. While the alignment of theextended layers 930 will tend to improve performance by positioningbringing the first structure 920 and second structure 940 closer, theextended gaps will tend reduce performance by spacing portions of thestructures further apart.

The device 900 can be fabricated by any of a variety of methodsincluding those set forth in the fabrication method 800 describedherein. In fabricating the device 900 the processes of providing adeposition structure 810, depositing a first layer with a first gap 820,depositing a second layer with a second gap overlapping the first gap todefine a third gap, forming a layered structure 830 and releasing thelayered structure 840 are generally performed as described, except theprocesses of depositing a first layer 820 and depositing a second layer840 are repeated to form the device 900 with the series of layers 922.

The exact number of layers that are deposited to form the device 900 canvary depending on the needs of the specific requirements of theapplication of the device 900. Also, the number and order of the firstand second layers can be modified as required.

To facilitate the deposition of additional layers over the initialsecond layer, the depositing process 840 can include the steps ofdepositing a sacrificial material to fill the second gap and the formingof the second layer to provide a continuous and sufficiently smoothdeposition surface.

Offset Actuator Apparatus Embodiments

To avoid or lessen the effect of the alignment of recessed layersforming extended sub-gaps, the structures can fabricated to be offset inthe alignment of the layers. During fabrication, a layer on onestructure which is not commonly aligned with a layer on the opposingstructure, is not limited to being separated by a gap which is at leastMFS wide. This is because with the layer offset, there is nocorresponding structure on the opposite structure. This allowspositioning of the end of the layer closer to the opposing structurethan is possible with commonly aligned layers which required a minimumMFS separation. After fabrication the offset structures can be actuatedinto a position where the offset layers are commonly aligned.

An embodiment of the apparatus having offset layers is set forth in FIG.10. Here, device 1000 includes a first structure 1020 and a secondstructure 1040 which are vertically offset from each other, such thatnone of the layers are commonly horizontally aligned. The amount of thevertical offset is a distance C10, which in this embodiment is equal tothe vertical height of the structures. As detailed herein, this verticaloffset allows for significantly closer horizontal positioning of the twostructures as compared to devices with horizontally aligned layers.

Because there are no horizontally aligned layers common to bothstructures, the layers are not limited in horizontal positioning by theMFS. As such, this embodiment provides the benefit that the structurescan be fabricated to have a horizontal separation of significantly lessthan the MFS, thus providing an increase to the performance of thedevice 1000. However, because of the vertical offset C10, to move thestructures 1020 and 1040 into a position where the layers are commonlyaligned (horizontally), requires a significant force to be applied. Thisrequires an associated high voltage differential to be applied to thestructure. The use of high voltages can result in shorting, burn-outs,charge accumulation, and/or the need to over size components toaccommodate the charge.

The first structure 1020 includes a set of layers 1022 having alignedends 1023. The second structure 1040 has a set of layers 1042 withaligned ends 1043. The ends 1023 and the ends 1043 are separated by alateral distance B10, which is capable of being less than the distanceA10. The distance A10 being at least the MFS. A gap 1060 is positionedbetween the first and second structures 1020 and 1040. As the structures1020 and 1040 move vertically towards each other, the gap 1060 willchange in its vertical size but will keep the width of the distance B10.

The device 1000 can be any of a variety of apparatuses including anactuator or more specifically a vertical comb actuator. The firststructure 1020 and second structure-1040 can each be an electrode, whichdepending on the embodiment, may be either movable (as shown) or fixedin position. Movement of the structures can be obtained by generating aforce between the structures. The direction of potential verticalmovement of the structures is shown in FIG. 10 by the arrows X1 and X2.The fixing of position of either one of the structures can be achievedby mounted it to any of a variety of structures (not shown), includingsubstrates, other structures, or the like.

Offset Actuator Fabrication Method Embodiments

A device (e.g. an actuator) which has structures positioned in offsetlayers generally can be fabricated by depositing a first set of layershaving a first structural region and a first sacrificial region and thendepositing a second set of layers having a second structural region,positioned over the first sacrificial region. The second set of layersmay also include a second sacrificial region which is placed over thefirst structural region, which abuts the second structural region andthat connects with the first sacrificial region. This defines a gapbetween the first and second structural regions, which can be sized lessthan the MFS.

The fabrication of the device 1000 can be achieved by a variety ofmethods including in at least one embodiment a method for fabricating aThree-dimensional structure having a minimum feature size 1100, whichincludes the processes of providing a deposition structure 1110,depositing a first set of at least one layer having a first structuralregion abutting a first sacrificial region 1120, depositing a second setof at least one layer having a second structural region positioned uponthe first sacrificial region forming a layered structure, wherein thesecond structural region is spaced a distance less than the minimumfeature size from the first structural region 1130, and releasing thelayered structure 1140.

The processes of providing a deposition structure 1110 is similar to thedeposition process 810 detailed above. That is, the deposition structurecan be either a substrate, a separate structure, or a sacrificialelement. Use of a sacrificial element provides the advantage of laterremoval during the releasing process, which can define a space formovement of structures of the device. The deposition structure can beformed to include a sufficiently smooth deposition surface for thedeposition of the first set of layers. The deposition structure andsurface can be formed by known methods, and be of know materials. To aidin the later electrodeposition over the deposition structure, thestructure can be conductive or have a conductive seed layer placed onit.

The process of depositing a first set of at least one layer having afirst structural region abutting a first sacrificial region 1120, canuse steps similar to those set forth in the process of depositing afirst layer 820 described herein. For example, the process can includerepeated applications of the steps of selectively depositing astructural material on a deposition surface, depositing a sacrificialmaterial to provide a continuous layer, and forming the layer to providea deposition surface. As these steps are repeated, the set of layerswith the first structural and sacrificial regions can be formed. Oneembodiment of a first structural region that can be obtained byoperation of this process is the second structure 1040 (with thesacrificial region removed as shown after the release process 840).

The selective deposition of the structural material the be done by thedescribed masks and masking techniques (e.g. INSTANT MASK™, MOA, AIM,ACC, methods detailed in the '630 patent and '637 patent disclosures),detailed above. Any of a variety of electrodeposition methods includingthe electrochemical fabrication methods can be employed to apply thestructural material. An advantage of this method is that since both theresulting structures are not fabricated in any common layers, theirseparation (horizontal) is not limited by the MFS. As a result the gapbetween the structures can be having a width less than the MFS.

After the structural material is selectively deposited on a layer, thesacrificial material can be deposited to form a continuous layer. Thesacrificial material can be deposited by any of a variety of methodsincluding a blanket electrodeposition. The sacrificial materialdeposition facilitates the forming (shaping and sizing) of the layer bymethods such as planarization to be employed. The forming of the layercan provide a deposition surface for the next layer.

Another process of the method 1100 is depositing a second set of atleast one layer having a second structural region positioned upon thefirst sacrificial region forming a layered structure, wherein the secondstructural region is spaced a distance less than the minimum featuresize from the first structural region 1130. This process can use stepssimilar to those described in both the process of depositing a first setof layers 1120 and the process of depositing a first layer 820 describedherein. The deposition process 1130 can include repeated applications ofthe steps of selectively depositing a structural material on adeposition surface, depositing a sacrificial material to provide acontinuous layer, and forming the layer to provide a deposition surface.Repeating the deposition of layers will build the second set of layerswith structural and sacrificial regions. The second structural region ispositioned over the sacrificial region of the first set of layers andthe sacrificial region of the second set of layers is set over the firststructural region. That is, the first sacrificial region and the secondsacrificial region are positioned to overlap each other to define a gapbetween the structures. One embodiment of a second structural regionthat can be obtained by operation of this process is the first structure1020 (with the sacrificial region removed as shown after the releaseprocess 840).

The selective deposition of the structural material the be done by thedescribed masks and masking techniques (e.g. INSTANT MASK™, MOA, AIM,ACC, methods detailed in the '630 patent and '637 patent disclosures),detailed above. Any of a variety of electrodeposition methods includingthe electrochemical fabrication methods can be employed to apply thestructural material. An advantage of this method is that since both theresulting structures are not fabricated in any common layers the gapbetween the structures is not limited by the MFS. Therefore, thestructures can be separated by a distance less than the MFS.

After the structural material is selectively deposited on a layer, thesacrificial material can be deposited to form a continuous layer. Thesacrificial material can be deposited by any of a variety of methodsincluding a blanket electrodeposition. The sacrificial materialdeposition facilitates the forming (shaping and sizing) of the layer bymethods such as planarization to be employed. The forming of the layercan provide a deposition surface for the next layer.

The process of releasing the layered structure 1140 is similar to thereleasing process 840 as set forth above. During this process thesacrificial material is removed to release the structure constructedduring the deposition. As described above, the sacrificial material canbe removed by any of a variety of methods including applying a chemicaletchant.

The exact number of layers that are deposited to form the device canvary depending on the needs of the specific requirements of theapplication of the device. Also, the order of the first and secondstructural regions can be reversed as required.

In an alternate embodiment, the method 1100 can further include aprocess of moving the first or the second structural region towards theother structural region, or moving the first and second structuralregions towards each other to reduce or eliminate the offset between thestructures.

Reduced Offset Actuator Embodiments

One way to achieve an increase in the performance of the apparatus ofthe invention is to reduce or minimize not only the gap separating thestructures (e.g. horizontal offset), but also any vertical offsetbetween the structures. Reducing the vertical offset can provide animprovement of the initial performance (movement from the initialposition) of the device. An embodiment of the apparatus of theApplicants' invention that reduces the vertical offset relative to theactuator 1000 (as shown in FIG. 10), is a device 1200 as shown in FIG.12. The device 1200 is similar to the device 1000, as it has twovertically shifted (offset) movable structures separated by a gapcapable of being sized smaller than the MFS. However, unlike the device1000, the device 1200 has at least one layer commonly aligned layer withlayer portions separated by a gap at least as wide as the MFS.

As FIG. 12 shows, the device 1200 includes a first structure 1220 and asecond structure 1240 separated by a gap 1260. The first structure 1220and the second structure 1240 are offset vertically from each other in amanner where only one layer in each structure is horizontally alignedwith a layer in the opposite structure. As detailed herein, this commonlayer allows for a reduced vertical offset between the first structure1220 and the second structure 1240.

The device 1200 can be a variety of different apparatuses such anactuator, including a vertical comb actuator. With the device as anactuator, the first structure 1220 and second structure 1240 can befixed and/or movable electrodes. By applying a voltage differentialbetween the structures, a force can be generated there between,resulting in movement of one or both of the structures.

The direction in which the structures in the embodiment of FIG. 12 arecapable of moving are shown by the arrows X1 and X2. In otherembodiments one of the structures can be fixed in position. This can beachieved by mounting the structure to any of a variety of structures(not shown), including substrates, structural elements, or the like. Thesize of the gap 1260 will vary as the structure(s) move.

The first structure 1220 includes a series of layers 1222 withvertically aligned ends 1223. In addition to the layers 1222 is arecessed or base layer 1226, with an end 1228 set back from the ends1223. The second structure 1240 includes a series of layers 1242 withvertically aligned ends 1243. The layers 1242 include an extended or caplayer 1246, with an end 1248 which is aligned with the ends 1243. Thehorizontal distance between the ends 1223 and the ends 1243 is adistance B12, and the distance of the end 1228 from the end 1248 is adistance A12. As further detailed herein, the distance A12 can be theMFS of the device 1200 and the distance B12 can be less than the MFS.

The device 1200 differs from the device 1000 (as shown in FIG. 10), asthe first and second structures of the device 1200 are verticallyshifted by one less layer, than the device 1000. As shown in FIG. 12,the device 1200 has one layer in each structure which are horizontallyaligned (e.g. in a common layer). Specifically, the recess layer 1226 isaligned with the extended layer 1246. By aligning the recessed layer1226 with the extended layer 1246, the amount of the vertical offset C12between the structures is reduced compared with that of the device 1000.

In embodiments where the separation distance B12 is less than the MFS,then the layers of each structure which are horizontally aligned must beseparated by a gap at least as wide as the MFS. As shown in FIG. 12, asub-gap 1262 is positioned between the end 1228 and the end 1248. Thewidth of the gap 1248 is the distance A12, which is at least thedistance of the MFS, but in some embodiments is equal to the MFS.

Therefore, while having one layer of each structure aligned does reducedthe overall vertical offset C12 between the structures, the horizontalsub-gap 1262 resulting from the effect of the MFS, increases thehorizontal distance between the structures at the most adjacent layers,namely aligned layers 1226 and 1246. By reducing the vertical offset C12between the first structure 1220 and the second structure 1240 (relativeto C10 of device 1000), the actuator 1200 is capable of increasedoverall performance.

As the first structure 1220 and the second structure 1240 move such thatthey are positioned closer to one another (i.e. from positions shown inFIG. 12, first structure 1220 moving downward in the X1 direction and/orthe second structure 1240 upward in the X2 direction), the size of thegap 1260 will reduce. The distance separating the first structure 1220and the second structure 1240 will be the distance B12, which as noted,can be well less than the MFS. By having a gap less than the MFS, theperformance of the device 1200 is increased by lowering the voltagerequired to achieve a desired force between the structures, and/or bygenerating a greater force for a specific voltage applied between thestructures.

An alternative to the embodiment shown in FIG. 12 has the sub-gap 1262positioned on the second structure 1240 and not the first structure1220, as shown. In this embodiment the end 1228 is positioned such thatit is aligned with the ends 1223, and the end 1248 is recessed back(e.g. to the right of) from the aligned ends 1243, such that thedistance between the ends 1228 and 1248 is still at least the MFS. Inanother embodiment the 1262 has portions positioned over both the firststructure 1220 and the second structure 1240, such that both the ends1228 and 1248 are recessed back from the ends 1223 and 1243,respectfully.

It should be clear to one skilled in the art that the device 1200 andits alternate embodiments can be formed by embodiments of thefabrication methods set forth herein.

As shown in FIG. 13, the vertical offset can be further reduced byutilizing additional commonly aligned layers between the structures. Inthe embodiment shown in FIG. 13 a device 1300 has a first structure 1320and a second structure 1340, which are separated by a gap 1360. As canbe seen, the vertical offset between the first structure 1320 and thesecond structure 1340 has been further reduced (compared to that of theembodiments of FIGS. 10 and 12) as two layers of the structures arecommonly horizontally aligned. The minimum separation between theextended portions the two structures remains at a distance which iscapable of being significantly less than the MFS.

The device 1300 can be an actuator, such as a vertical comb actuator.Also, the first structure 1320 and second structure 1340 can be fixedand/or movable electrodes (as shown). By applying a voltage differentialbetween the structures, a force can be generated between them, resultingin movement of one or both of the structures.

The direction in which the structures in the embodiment of FIG. 13 arecapable of moving are shown by the arrows X1 and X2. In otherembodiments, one of the structures can be fixed in position. This can beachieved by mounting the structure to any of a variety of structures(not shown), including substrates, structural elements, or the like. Thesize and shape of the gap 1360 will vary as the structure(s) move.

The first structure 1320 includes a series of layers 1322 withvertically aligned ends 1323. The structure 1320 also includes aextended or base layer 1326 and a recessed layer 1330. The extendedlayer 1326 has an end 1328 aligned with the ends 1323 and the recessedlayer includes an end 1332 set back from the ends 1323.

The second electrode 1340 includes a series of layers 1342 withvertically aligned ends 1343. A extended or cap layer 1348 and arecessed layer 1350 are positioned over the series 1342. The extendedlayer 1346 has an end 1348, which is aligned with the ends 1343. Therecessed layer 1350 has an end 1352 positioned back from the ends 1343.

The horizontal distance between the ends 1323 and 1328 of the firststructure 1320, and the ends 1343 and 1348 of the second electrode 1340is a distance B13. The distance between the ends 1328 and 1352 as wellas between the ends 1332 and 1348, of the two commonly aligned layers,is the distance A13. As further detailed herein the minimum of thedistance A13 is the MFS of the device 1300.

The device 1300 differs from the device 1200 (as shown in FIG. 12), asthe first and second structures of the device 1300 are verticallyshifted by another layer less, than that of the device 1200. As shown inFIG. 13, the device 1300 has two layers in each structure which arehorizontally aligned (e.g. fabricated in a common layer). Specifically,the extended layer 1326 is aligned with the recessed layer 1350 and therecessed layer 1330 is aligned with the extended layer 1346.

By aligning two layers in each structure in the device 1300, the amountof the vertical offset C13 between the structures is reduced comparedwith that of the actuator 1200. In embodiments of the invention wherethe separation distance B13 is less than the MFS, then the layers ofeach structure which are horizontally aligned, must be separated by agap at least as wide as the MFS. This gap can be positioned at or inbetween the first structure 1320 and/or the second structure 1340.

In the position of the device 1300 as shown, the gap 1360 includes afirst sub-gap 1362 and a second sub-gap 1634. The first sub-gap 1362 ispositioned between the ends 1328 and 1352, while the second sub-gap 1364is set between the ends 1332 and 1348. The widths of the sub-gaps 1362and 1364 are the distances A13, which is at least the MFS, and in someembodiments is equal to the MFS.

By further reducing the vertical offset between the first and secondstructures, in this embodiment the initial performance of the device1300 can be increased as compared to the embodiments of FIGS. 10 and 12.As the first structure 1320 and the second structure 1340 move such thatthey are positioned closer to one another (i.e. first structure 1320downward and/or the second structure 1340 upward), the overall size ofthe gap 1360 will reduce.

By reducing the vertical offset C13 and by having the gap 1360 withdimensions less than the MFS, the performance of the actuator 1300 isincreased by lowering the voltage required to achieve a desired forcebetween the structures, and/or by generating a greater force for aspecific voltage applied between the structures.

An alternate to the embodiment shown in FIG. 13 has the sub-gaps 1362and 1364 positioned over the opposite structures from their positions asshown. In another embodiment, the gaps 1362 and 1364 have portionspositioned over both the first structure 1320 and the second structure1340, such that the ends 1328 and 1332 are positioned back from thealigned ends 1323, and the ends 1348 and 1352 are positioned back fromthe aligned ends 1343.

It should be clear to one skilled in the art that the device 1300 andits alternate embodiments can be formed by embodiments of thefabrication methods set forth herein.

Another embodiment of the Applicant's invention has additionalhorizontally aligned layers to further reduce the vertical offsetbetween the structures of the device. As shown in FIG. 14, the device1400 includes a first structure 1420 and a second structure 1440. Thestructures have four layers commonly aligned layers so that the verticaloffset is reduced. Separating the structures is a gap 1460, which at hasminimum separation between the structures being a distance capable ofbeing significantly less than the MFS.

The device 1400 can be employed in a variety of applications, in atleast one embodiment, the device is an actuator, or more specifically avertical comb actuator. The first structure 1420 and the secondstructure 1440 can be fixed and/or movable electrodes. As shown, thefirst structure 1420 can move in the X1 direction and/or the secondstructure 1440 can move in the X2 direction. In other embodiments one ofthe structures can be fixed in position by mounting the structure to anyof a variety of structures (not shown). Movement of either or bothstructures can be achieved by applying a voltage differential betweenthe electrodes.

The first structure 1420 includes a series of aligned layers 1422,extended layers 1426, and recessed layers 1430. Each layer of the seriesof aligned layers 1422 include an end 1423, which are aligned with oneanother. The extended layers 1426 have ends 1428 which are aligned withthe ends 1423. The recessed layers 1430 have ends 1432, which arerecessed back from the ends 1423 and 1428. Likewise, the secondstructure 1440 includes a series of aligned layers 1442, extended layers1446, and recessed layers 1450. Each layer of the series of alignedlayers 1442 include an end 1443, which are aligned with one another. Theextended layers 1446 have ends 1448 which are aligned with the ends1443. The recessed layers 1450 have ends 1452, which are recessed backfrom the ends 1443 and 1448.

In the position of the device 1400 as shown, the gap 1460 includes firstsub-gaps 1462 and second sub-gaps 1464. The first sub-gaps 1462 arepositioned between the ends 1428 and 1452 and the second sub-gaps 1464between the ends 1432 and 1448. The widths of the sub-gaps 1462 and 1464are a distance A14, which is at least the MFS and in some embodiments isequal to the MFS.

In alternate embodiments to that shown in FIG. 14, the specifichorizontal positioning of the sub-gaps can vary along each aligned layer(e.g. positioned in part on either of the two structures). In otheralternates, the positions of the ends of each layer in the device 1400can vary and are not necessarily aligned as shown.

Clearly as the positions of the first structure 1420 and the secondstructure 1440 move relative to one another, the size and shape of thegap 1460 will change, and the sub-gaps 1462 and 1464 will no longer bedefined in the gap 1460 as shown in FIG. 14. The gap 1460 provides aminimum separation between the first and second structures of thedistance B14. The distance B14 can be less than the MFS of the device1400. While the in other embodiments the ends of the layers of thedevice 1400 can vary in position such that they are not aligned, asshown, aligning the ends 1432 and 1428 and the ends 1443 and 1448,provides certain benefits. One such benefit is that the distance B14 canbe minimized as the common vertical alignment will avoid needing to seta certain separation just to allow clearance of the ends extending thefarthest out towards the opposite structure. Another benefit is that themaximum amount of structure can be place at the minimum distance ofseparation without contact between the structures, to get the greatestamount of performance of the device 1400.

The first structure 1420 and the second structure 1440 are verticallyoffset from each other by a distance C14. As noted, this offsetpositions the structures such that four layers of one structure arehorizontally aligned with the four layers of the other electrode. Theembodiment of the invention shown in FIG. 14 has a reduced verticaloffset compared to that of other embodiments of the invention (as shownin FIGS. 10, 12 and 13). With the vertical offset further reduced, theinitial performance of the device 1400 can be greater relative to theseother embodiments.

It should be clear to one skilled in the art that the device 1400 andits alternate embodiments can be formed by embodiments of thefabrication methods set forth herein.

Some embodiments of the invention also include the embodiment shown inFIG. 15. While this embodiment has a reduced vertical offset achieved byhaving a greater number of layers that are horizontally aligned, asdetailed herein, it is also capable of improved operational performancefrom the particular arrangement of its layers. The structures have sixlayers commonly aligned layers so to reduce the vertical offset. Thedevice 1500 includes a first structure 1520 and a second structure 1540,separated by a gap 1560. The gap 1560 has a minimum separation betweenthe structures of a distance which is capable of being significantlyless than the MFS.

In at least one embodiment, the device 1500 is an actuator, and in otheris a vertical comb actuator. The first structure 1520 and secondstructure 1540 can be fixed and/or movable electrodes. As shown, thefirst structure 1520 can move vertically in the X1 direction and/or thesecond structure 1540 can move vertically in the X2 direction. In otherembodiments, one of the structures can be fixed in position by mountingthe structure to any of a variety of structures (not shown). With one orboth movable electrodes, movement can be achieved by applying a forcethrough a voltage differential between the electrodes.

As shown in FIG. 15, the first structure 1520 includes a series oflayers 1522, a pair of extended layers 1526, a pair of recessed layers1530, a extended layer 1534 and a recessed layer 1536. Each layer of theseries of aligned layers 1522 include an end 1523. The ends 1523 arevertical aligned with one another. The pair of extended layers 1526 haveends 1528, which are aligned with each other and with the ends 1523. Thepair of recessed layers 1530 have ends 1532 which are positioned backfrom the ends 1523 and 1528. The extended layer 1534 has an end 1535that is also aligned with the ends 1523 and 1528 and an end 1537 of therecessed layer 1536 is aligned with the ends 1532.

The second structure 1540 includes a series of layers 1542, a extendedlayer 1546, a recessed layer 1550, a pair of extended layers 1554, and apair of recessed layers 1556. Each layer of the series of aligned layers1542 includes an end 1543. The ends 1543 are vertical aligned with oneanother. The extended layer 1546 has an end 1548 that is also alignedwith the ends 1543 and the recessed layer 1550 has an end 1552. The pairof extended layers 1554 have ends 1555, which are aligned with eachother and with the ends 1543 and 1548. The pair of recessed layers 1556have aligned ends 1557 which are positioned back from the ends 1543,1555 and 1548, and aligned with end 1552.

In the position of the device 1500 as shown in FIG. 15, the gap 1560includes a first sub-gap 1562, a second sub-gap 1564, a third sub-gap1566 and a fourth sub-gap 1568. The first sub-gap 1562 is positionedbetween the ends 1528 and the ends 1557, the second sub-gap 1564 betweenthe ends 1532 and 1555, the third sub-gap 1566 between the ends 1535 and1552, and the fourth sub-gap 1568 between the ends 1537 and 1548. Thefirst sub-gap 1562 and second sub-gap 1564 both have a thickness(vertical height) of two material layers, while the third sub-gap 1566and the fourth sub-gap 1568 are only one layer thick. The lengths(horizontal width) of the sub-gaps 1562, 1564, 1566 and 1568 are thedistance A15, which is at least the MFS and in some embodiments is equalto the MFS.

In alternate embodiments to that shown in FIG. 15, the specifichorizontal positioning of the sub-gaps can vary along each aligned layeror layers (e.g. positioned in part on either of the two structures).However, due to construction limitations, the minimum width of thesub-gaps, regardless of their specific positioning is the MFS. While thein other embodiments the ends of the layers of the device 1500 can varyin position such that they are not aligned, as shown, aligning the endsof the extended layers allows the distance B15 to be minimized as thecommon vertical alignment will avoid needing to set a certain separationto allow physical clearance of the structures. Also, the maximum amountof structure can be place at the minimum distance of separation.

As the positions of the first structure 1520 and the second structure1540 move relative to one another, the size and shape of the gap 1560will change, and the sub-gaps will no longer be defined as shown.

In its initial position, as shown in FIG. 15, the device 1500 has thefirst structure 1520 and the second structure 1540 with a verticaloffset of the distance C15. In this offset position the electrodes havesix material layers on each electrode that are horizontally aligned withsix material layers on the other electrode. The embodiment of theinvention shown in FIG. 15 has a reduced vertical offset compared tothat of other embodiments of the invention (as described herein). Withthe vertical offset further reduced, the initial performance of thedevice 1500 can be increased as compared to the other embodiments.

This embodiment of the invention is also capable of providing improvedperformance as a result of the specific arrangement of the layers andthe sub-gaps separating them. This is due to the fact that as the firststructure 1520 and the second structure 1540 move towards each other,fewer of the recessed layers (e.g. layers 1530, 1536, 1550 and 1556)tend to align with each other to create extended sub-gaps. Extendedsub-gaps reduce performance (e.g. less force produced for a givenvoltage applied) by significantly increasing the distance between theends of the recessed layers.

For example, as the first structure 1520 and the second structure 1540are moved a distance one layer closer to each other from the initialposition shown in FIG. 15, only two extended sub-gaps are formed. Inthis position, of the ten layers of each structure 1520 and 1540, onlytwo of the recessed layers 1536 with 1550 and lower 1530 with upper1556, align to form extended sub-gaps. However, three of these layers ofeach structure, lower layer 1526 with upper layer 1542, 1534 with upper1554, and 1546 with lower 1522, are positioned the minimum distance B15apart from other layers. As the structures continue to move towards eachother, the number of extended sub-gaps generated will be one or two atthe most.

The device 1500 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

The next embodiment of the invention is shown in FIG. 16, wherein thedevice 1600 includes a first structure 1620 and a second structure 1640,separated by a gap 1660. The gap 1660 provides a minimum separationbetween the structures of a distance which is capable of beingsignificantly less than the MFS.

This embodiment is able to provide improved operational performance byreducing the vertical offset between the structures and by thearrangement of the aligned layers. A reduced vertical offset of thestructures is achieved by having a greater number of layers that arealigned horizontally. That is, by constructing with a greater portion ofthe structures in common aligned layers, the vertical offset of thisembodiment can be reduced. Of course, using common layers tends toincrease the horizontal offset because of the minimum spacing requiredby the MFS. The effect of the MFS spacing can be reduced by thearrangement of the layers in the structure. Specifically, with themovement of the structures 1620 and 1640 towards one another, thearrangement of the layers can reduce the effect of the MFS and increasethe performance of the device 1600.

In at least one embodiment, the device 1600 is an actuator or a verticalcomb actuator. The first structure 1620 and second structure 1640 can befixed and/or movable electrodes. As shown, the first structure 1620 canmove vertically in the X1 direction and/or the second structure 1640 canmove vertically in the X2 direction. In other embodiments, one of thestructures can be fixed in position by mounting the structure to any ofa variety of structures (not shown). With one or both movableelectrodes, movement can be achieved by applying a force through avoltage differential between the electrodes.

As shown in FIG. 16, the first structure 1620 includes a series oflayers 1622, a set of four of extended layers 1626, a set of threerecessed layers 1630, a pair of extended layers 1634 and a recessedlayer 1636. Each layer of the series of aligned layers 1622 includes anend 1623. The ends 1623 are vertical aligned with one another. The setof extended layers 1626 have ends 1628, which are aligned with eachother and with the ends 1623. The set of recessed layers 1630 have ends1632 which are positioned back from the ends 1623 and 1628. The pair ofextended layers 1634 have ends 1635 that are also aligned with the ends1623 and 1628. The recessed layer 1636 is aligned with the ends 1632.

Similarly, the second structure 1640 includes a series of layers 1642, aextended layer 1646, a pair of recessed layers 1650, a set of threeextended layers 1654, and a set of four recessed layers 1656. Each layerof the series of aligned layers 1642 includes an end 1643. The ends 1643are vertical aligned with one another. The extended layer 1646 has anend 1648 that is also aligned with the ends 1643 and the recessed layers1650 have ends 1652. The set of extended layers 1654 have ends 1655,which are aligned with each other and with the ends 1643 and 1648. Theset of recessed layers 1656 have aligned ends 1657 which are positionedback from the ends 1643, 1655 and 1648, and are aligned with ends 1652.

In the position of the device 1600 as shown in FIG. 16, the gap 1660includes a first sub-gap 1662, a second sub-gap 1664, a third sub-gap1666 and a fourth sub-gap 1668. The first sub-gap 1662 is positionedbetween the ends 1628 and the ends 1657, the second sub-gap 1664 betweenthe ends 1632 and 1655, the third sub-gap 1666 between the ends 1635 and1652, and the fourth sub-gap 1668 between the ends 1637 and 1648. Thefirst sub-gap 1662 has a thickness of four layers, the second sub-gap1664 of three layers, the third sub-gap 1666 of two layers and thefourth sub-gap 1668 is only one layer thick. The lengths (horizontalwidth) of the sub-gaps 1662, 1664.1666 and 1668, are the distance A16,which is at least the MFS, and in some embodiments is equal to the MFS.

In alternate embodiments to that shown in FIG. 16, the specifichorizontal positioning of the sub-gaps can vary along each aligned layeror layers (e.g. positioned in part on either of the two structures).However, due to construction limitations, the minimum width of thesub-gaps, regardless of their specific positioning is the MFS.

As the positions of the first structure 1620 and the second structure1640 move relative to one another, the size and shape of the gap 1660will change, and the sub-gaps will no longer be defined as shown.

In its initial position, as shown in FIG. 16, the device 1600 has thefirst structure 1620 and the second structure 1640 with a verticaloffset of the distance C16. In this offset position the electrodes haveten material layers on each electrode that are horizontally aligned withten material layers on the other electrode. The embodiment of theinvention shown in FIG. 16 has a reduced vertical offset compared tothat of other embodiments of the invention (as described herein). Withthe vertical offset further reduced, the initial performance of thedevice 1600 can be increased as compared to the other embodiments.

This embodiment of the invention is also capable of providing improvedperformance as a result of the specific arrangement of the layers andthe sub-gaps separating them. This is due to the fact that as the firststructure 1620 and the second structure 1640 move towards each other,only a limited number of the recessed layers (e.g. layers 1630, 1636,1650 and 1656) tend to align with each other to create extendedsub-gaps. Extended sub-gaps reduce performance (e.g. less force producedfor a given voltage applied) by significantly increasing the distancebetween the ends of the recessed layers.

As the first structure 1620 and the second structure 1640 move towardseach other from their initial positions shown in FIG. 16, a maximum ofthree extended gaps are formed. However, up to eleven layers arepositioned at or less than the MFS apart, with some a distance A16 apartand some a closer distance B16 apart.

Alternate embodiments to those set forth herein include varying theconfiguration of the layering of the device. Namely, the number ofhorizontally aligned layers between the two structures can vary suchthat there are more or less layers than detailed herein. Also, theparticular arrangement of the layers (flush and/or recessed) and thepositioning of the sub-gaps (over one or both of the structures), can beany of a wide variety. As noted herein, while some embodiments do notalign the layers, or otherwise position the layers as shown, aligningthe layers allows increased performance by positioning more of thestructures closer together.

The device 1600 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

To further reduce the vertical offset, the structures can be arranged tohave an even greater amount of the layers commonly aligned. Anembodiment of a device that has a minimum offset or layer shift (e.g. asingle layer) is shown in FIG. 17. A device 1700 includes a firststructure 1720, a second structure 1740 and a gap 1760 separating thetwo.

As can be seen, in this embodiment the layering of the two structures isnot completely aligned. The layering has been shifted or displaced by alayer in each structure, so that the top layer of one structure and thebottom of the other structure do not have a corresponding layer in theother structure. As detailed herein, this arrangement of layers allowsthe positioning of the structures at distances less than the minimumfeature size (MFS), providing increasing performance of the device.

While the device 1700 can be any of a variety of apparatuses and thestructures 1720 and 1740 can be a number of different components ofthose apparatuses. In certain embodiments of the Applicants' inventionthe device 1700 is an actuator and the structures 1720 and 1740 aremovable first and second electrodes, respectfully. In specificembodiments, the device 1700 is a vertical comb actuator (VCA), thefirst structure 1720 is a fixed electrode and the second structure 1740is a movable electrode.

Depending on the embodiment, the second structure 1740 can be capable ofmoving in the direction X2 (e.g. vertically relative to the planarstructure of the device 1700), as a force is applied between thestructures 1720 and 1740. One method of creating such a force can be byapplying an electrical differential between the structures 1720 and1740, which in such cases are at least partially electricallyconductive. The gap 1760 separating the structures will vary in size asthe second structure 1740 moves relative to the first. With thestructures positioned as shown in FIG. 17, the gap 1760 includessub-gaps 1762 which are positioned between ends of the commonly alignedlayers of the structures.

The distance between the ends of the aligned layers, or the width of thesub-gaps 1762, is a distance A17. While length of the distance A17 canvary depending on the embodiment, the minimum length is the MFS of thefabrication process used. The second structure 1740 is constructed sothat its layers are shifted or displaced upward by one layer compared tothe layering of the first structure 1720. This allows certain layers ofthe first structure 1720 and the second structure 1740 to be positionedonly a distance B17 from the opposing structure. As can be seen, thedistance B17 is sufficiently less than the distance A17, and as such canbe well less than the MFS. With the structures 1720 and 1740 capable ofbeing positioned closer to one another than the MFS, the overallperformance of the device 1700 can be increased as compared to theoperation of prior devices.

Depending on the embodiment, the first structure 1720 can be configuredto remain stationary and can be attached to any of a variety ofstructures (not shown), including a substrate or another structuralelement. The first structure 1720 includes a series of recessed layers1722 and an extended or base layer 1726. The layers 1722 are positionedupon the extended layer 1726 and each layer includes an end 1723. Inthis embodiment, the ends 1723 are substantially aligned with eachother, although as described herein, other alignments are possible. Thelayers 1722 include a cap layer 1730 with an end 1732.

The extended layer 1726 extends outward from the rest of the firststructure 1720 and terminates in an end 1728. The extension of the baselayer 1726 allows the positioning of the end 1728 the distance B17 tothe second structure 1740. Likewise, the end 1732 of the cap layer 1730is also positioned a distance B17 from the second structure 1740.

In the embodiment shown in FIG. 17, the second structure 1740 isconfigured to move relative to the first (fixed) structure 1720. Thesecond structure 1740 includes a series of recessed layers 1742 and anextended or cap layer 1746. The layers 1742 are positioned upon eachother and under the extended layer 1746. Each layer of the series 1742includes an end 1743, which is positioned opposite to the ends 1723 andseparated there between with the sub-gaps 1762.

As noted, the size of the space 1762 is limited by the constraints,namely by the MFS, of the particular method of fabrication. During thefabrication of the layers 1722 and 1742, as each layer of material isdeposited, a sub-gap 1762 is constructed along the layer in order toseparate and define the structures 1720 and 1740. While the positioningof the sub-gaps 1762 can vary in each layer (e.g. a steppedarrangement), the width of the sub-gaps 1762 can be no less than theMFS.

In FIG. 17 it can be seen that at some points, the distance between thefirst structure 1720 and the second structure 1740, can be less than theMFS. This is achieved by configuring the device 1700 so that certainlayers do not have a corresponding layer positioned across from them onthe opposite structure. That is, so that some layers are alignedopposite to a blank layer or region on the other structure. In thismanner without opposing structure to define a MFS limited space betweenthe two structures, the particular layer can be extended so that it ispositioned within the MFS to the next adjacent layer in the oppositestructure. This results in the layering of the two structures beingoffset or shifted by a distance C17, which in the embodiment shown, isone layer thick.

In the device 1700, the extended layer 1726 and the extended layer 1746lack a corresponding layer on the opposite structure, and they eachextend towards the opposite structure to a distance B17. That is, theextended layer 1726 extends out from the first structure 1720 to adistance B17 from the end 1752 of the layer 1750. Likewise, the extendedlayer 1746 extends outward from the second structure 1740 until it iswithin the distance B17 of the end 1732 of the layer 1730. It should benoted, that while in the embodiment shown, the extended layer 1726 andthe extended layer 1746 each extend to the same distance B17 from theopposite structure, that the structures can be fabricated such that thetwo separation distances are not the same.

The device 1700 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

Staggered Structure Actuator Embodiments

While the embodiment of the device 1700 does reduce the vertical offset,due to the number of commonly aligned layers a significant horizontaloffset is formed by the sub-gaps being limited to a minimum width of theMFS. To further reduce the overall offset between the structures,another embodiment of the invention staggers the positioning of thelayers (and the sub-gaps). As shown in FIG. 18, in this embodiment thelayers of each structure have been positioned to form a steppedarrangement. As with the previous embodiment, the spacing betweenaligned layers continues to be restricted by the MFS; however the baseand cap layers can be positioned within the MFS. In this embodiment, thelayers of each electrode have been positioned to end in a coordinatedstepped arrangement, allowing the mean distance between the twoelectrodes to be further reduced.

A device 1800 includes a first structure 1820 separated by a gap 1860from a second structure 1840. The device 1800 can be any of a variety ofapparatuses including an actuator or more specifically a vertical combactuator. The first structure 1820 can be an electrode which in someembodiments is fixed in position. Likewise, the second structure 1840can be an electrode which in certain arrangements is movable. Themovement of the second structure 1840 in the embodiment shown is capableof moving in direction X2 upon application of a force between thestructures. In embodiments with the first structure being movable, thestructure can move in a direction X1, as shown. As the second structure1840 moves, the size and shape of the gap 1860 will vary. As shown, thegap 1860 includes sub-gaps 1862, set between the ends of the commonlyaligned layers of the structures.

The first structure 1820 can be configured to remain stationary by beingmounted to (i.e. built upon) any of a variety of structures (not shown),including substrates, other layered structures, etc. The first structure1820 includes a series of layers 1822, an extended or base layer 1826,and a recessed or cap layer 1830. The series of layers 1822 arepositioned upon the base layer 1826 and then progressively on each otherin a stepped configuration. The layers 1822 include ends 1823, whichalso stepped.

The second structure 1840 includes a series of layers 1842, an extendedor cap layer 1846, and a recessed or base layer 1850. The layers 1842are positioned upon each other in a stepped overhanging configurationdepending from the extended layer 1846. Each layer of the layers 1842includes an end 1843, which is positioned opposing one of the ends 1823.The ends 1823 and 1843 are separated by a sub-gap 1862 having a lengthA18. Because each sub-gap 1862 is set between portions of aligned (i.e.commonly constructed) layers, the minimum length of the sub-gaps 1862 isthe MFS of the device 1800.

Like with the device 1700 (as shown in FIG. 17), the extended layers1826 and 1846 each extend to a distance that is less than the MFS fromthe opposite structure. Specifically, the extended layer 1826 extendsoutward from the rest of the first structure 1820 towards the secondstructure 1840. This results in an end 1828 of the base layer 1826 beinga distance B18 from the second structure 1840. Likewise, the extendedlayer 1846 extends outward from the remaining portion of the secondstructure 1840 until it is within a distance B18 of an end 1832 of therecessed layer 1830 of the first structure 1820. This is possible as theextended layers 1826 and 1846 each lack a corresponding layer positionedacross from them on the opposite electrode (which is shifted by onelayer). In this manner without a layer positioned on the opposingelectrode to define a MFS limited space there between, the particularlayer can be extended so that it is positioned a distance within the MFSto other layers of the opposing structure. This results in the layeringof the two structures being offset or shifted by a distance C18, whichin the embodiment shown, is one layer thick.

However, a distinct difference between the embodiments of the device1700 and the device 1800 is that with the device 1800, the layers of thestructures 1820 and 1840 are positioned in a generally staggeredarrangement, as shown in FIG. 18. By staggering the layers in a steppedmanner, the overall or mean distance between the structures can befurther reduced. This distance reduction allows an additional increasein the performance of the device 1800.

The device 1800 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

FIG. 19 sets forth an additional embodiment, which, like the embodimentof FIG. 18, the layers of structures have been set in a steppedarrangement. By utilizing a stepped configuration, the overallseparation of the structures can be reduced to increase performance ofthe device. Similar to other embodiments, the spacing between thealigned layers continues to be restricted by the MFS, but by offsettingthe layering, the extended layers of the first and second structures arecapable of being positioned within the MFS of the opposite structure.

A device 1900 includes a first structure 1920, a second structure 1940and a gap 1960 separating them. The device 1900 can be any of a varietyof apparatuses including an actuator or a vertical comb actuator. Thefirst structure 1920 can be an electrode which may be fixed in positionby being mounted to any of a variety of structures (not shown),including substrates, other structures, etc, or movable. With the firststructure being movable, it can move in a direction X1. The secondstructure 1940 can be an electrode which may be movable in the X2direction or can be fixed with the first structure 1920 being movable.Movement of the structures varies the overall size of the gap 1960. Thegap 1960 includes sub-gaps 1962, positioned between the ends of thecommonly aligned layers of the structures.

The first structure 1920 includes a series of layers 1922 with ends1923, an extended or base layer 1926 with an end 1928, and a recessed orcap layer 1930 with an end 1932. The series of layers 1922 arepositioned upon the extended layer 1926 and then progressively upon eachother in a double-layer stepped configuration. The second structure 1940includes a series of layers 1942 with ends 1943, an extended or caplayer 1946 with an end 1948, and a recessed or base layer 1950 with anend 1952. The layers 1942 are positioned upon each other in adouble-layer stepped overhanging configuration, which depends from theextended layer 1946. Each end 1943, is positioned opposing an end 1923.Between each aligned set of ends 1923 and 1943 is a sub-gap 1962. Eachsub-gap 1962 has a length A19, which itself has a minimum length of theMFS of the device 1900.

The extended layers 1926 and 1946 each extend to a distance that can beless than the MFS from the opposite electrode. Specifically, the end1928 is a distance B19 from the second structure 1940 and the end 1948is set a distance B19 to the first structure 1920. This is possible asthe extended layers 1926 and 1946 each lack a corresponding layerpositioned across from them on the opposite electrode to define a MFSlimited space between the electrodes. This results in the layering ofthe two structures being offset or shifted by a distance C19, which inthe embodiment shown, is one layer thick.

It should be clear to one skilled in the art that the device 1900 andits alternate embodiments can be formed by embodiments of thefabrication methods set forth herein.

In other embodiments of the invention more than one configuration of thelayers of the structures is used. This allows the layers of thestructures to be arranged to meet the specific requirements of the usewhich the embodiment is employed. The configurations of layers used canmatch or be similar to that set forth herein, namely, aligned layer endsand the stepped layering. It should be clear to one skilled in the artthat any combination of the layer configurations set forth herein can becombined to form an embodiment of the invention.

Regional Patterned Actuator Embodiments

In other embodiments of the invention, the configuration of the layersvaries not only vertically and horizontally as has been shown, but alsoalong a depth of the device. FIG. 20 shows one example of an embodimentof a device 2000 that is configured with the layers varying along thedevice's depth. As can be seen, the pattern of the extended and recessedsections of the layers alternate vertically and across the depth of boththe first structure 2020 and the second structure 2040.

The first structure 2020 and the second structure 2040 are separated bya gap 2060. With the device 2000 being an actuator, or more specificallya vertical comb actuator, the first structure 2020 can be an electrodewhich may be capable of moving in the direction X1, while the secondstructure 2040 an electrode which may be capable of moving in thedirection X2.

The device 2000 can be employed in a variety of applications, in atleast one embodiment, the device is an actuator, or more specifically avertical comb actuator. The first structure 2020 and the secondstructure 2040 can be fixed and/or movable electrodes. As shown, thefirst structure 2020 can move in the X1 direction and/or the secondstructure 2040 can move in the X2 direction. In other embodiments one ofthe structures can be fixed in position by mounting the structure to anyof a variety of structures (not shown). Movement of either or bothstructures can be achieved by applying a voltage differential betweenthe electrodes.

The first structure 2020 includes a series of aligned layers 2022,extended layers 2026, and recessed layers 2030. Each layer of the seriesof aligned layers 2022 include an end 2023, which are vertically alignedwith one another. The extended layers 2026 have ends 2028 which arealigned with the ends 2023. The recessed layers 2030 have ends 2032,which are recessed back from the ends 2023 and 2028. Along its depth,the first structure 2020 has a series of sections 2080 which include afirst or base section 2082 and a second or shifted section 2084. As canbe seen below the series of layers 2022 the first section 2082 and thesecond section 2084 alternate in extended and recessed portions alongthe depth of the first structure 2020. The width of the sections 2080 isthe distance D20. Depending on the embodiment, due to fabricationlimitations, the minimum size of the width D20 is the MFS.

The second structure 2040 includes a series of aligned layers 2042,extended layers 2046, and recessed layers 2050. Each layer of the seriesof aligned layers 2042 include an end 2043, which are vertically alignedwith one another. The extended layers 2046 have ends 2048 which arealigned with the ends 2043. The recessed layers 2050 have ends 2052,which are recessed back from the ends 2043 and 2048. The secondstructure 2040 has a series of sections 2090 which include a first orbase section 2092 and a second or shifted section 2094. Above the seriesof layers 2042, the first section 2092 and the second section 2094alternate in extended and recessed portions along the depth of thesecond structure 2040. The width of the sections 2090 is the distanceD20, which has a minimum size of the MFS.

In the position of the device 2000 as shown, the gap 2060 includes firstsub-gaps 2062 and second sub-gaps 2064. The first sub-gaps 2062 arepositioned between the ends 2028 and 2052 and the second sub-gaps 2064between the ends 2032 and 2048. The widths of the sub-gaps 2062 and 2064are a distance A20, which is at least the MFS and in some embodiments isequal to the MFS.

With the vertical and depth-wise alternating pattern of extended andrecessed layers in the device 2000, an effective surface on eachstructure is defined from the pattern of extended layers. As shown inFIG. 20, an effective surface of the first electrode 2020 is defined bythe ends 2023 and 2028 of the extended layers 2022 and 2026. Likewise,the second structure 2040 has a second effective surface (not shown)defined by the ends 2043 and 2048 of the extended layers 2042 and 2046.The effective surfaces are positioned a distance B20 apart, which iscapable of being substantially less than the MFS.

In alternate embodiments of the invention, different patterns ofextended and recessed layers, from those shown in FIG. 20, are used inthe sections 2080 and 2090. For example, the pattern of layers set forthin any of the embodiments of the invention shown in FIGS. 12-16 (devices1200, 1300, 1400, 1500 and 1600). Each section can have a differentpattern as desired. Further, as shown in FIG. 20, the patterns may beshifted by one or more layers. By varying the pattern of the layering indifferent sections along the depth of the device, the device is capableof providing improved performance by minimizing the number of extendedsub-gaps and maximizing the number of shortened sub-gaps over themovement of the structures relative to one another. In other alternateembodiments, the specific horizontal positioning of the sub-gaps canvary along each aligned layer (e.g. positioned in part on either of thetwo structures). In other alternates, the positions of the ends of eachlayer in the device 2000 can vary and are not necessarily aligned asshown. While the in other embodiments the ends of the layers of thedevice 2000 can vary in position such that they are not aligned, asshown, aligning the ends 2032 and 2028 and the ends 2043 and 2048,provides the benefit of closer structure positioning.

The device 2000 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

Horizontal Comb Actuator Embodiments

Some embodiments of the invention can also be embodied in a horizontalcomb actuator (HCA) for movement or actuation of other structures in agenerally horizontal direction. Shown in FIGS. 21A and 21B is anotherembodiment of the invention, wherein a device 2100 includes a firststructure 2120 and a second structure 2140 separated by a gap 2160. FIG.21A showing a side view and FIG. 21B a top view of the device 2100.

The first structure 2120 includes a set of layers having alternatingrecessed layers 2126 and extended or flush layers 2130. The recessedlayers have ends 2128 positioned aligned with each other and theextended layers 2130 have aligned ends 2132. Similarly, the secondstructure 2140 includes a set of layers having alternating extended orflush layers 2146 and recessed layers 2150. The extended layers 2146have aligned ends 2148 and the recessed layers 2150 have aligned ends2152. Because of the staggered positioning of the layers the extendedends 2130 and 2148 are positioned a distance B21 apart. Since theextended ends 2130 and 2148 are not in the same layers, the distance B21is capable of being significantly less than the MFS.

The gap 2160 includes first sub-gaps 2162 and second sub-gaps 2164 whichalternate along the gap 2160. The first sub-gaps 2162 are positionedbetween the recessed ends 2130 and the extended ends 2148. The secondsub-gaps 2164 are positioned between the extended ends 2130 and therecessed ends 2152. While the sub-gaps 2162 and 2164 can vary in theirwidth, a distance A21, the width is limited to a minimum of the MFS ofthe device 2100.

The device 2100 can be employed in a variety of applications, in atleast one embodiment, the device is an actuator, or more specifically ahorizontal comb actuator. The first structure 2120 and the secondstructure 2140 can be fixed and/or movable electrodes. Depending on theembodiment, either the first structure 2120 and/or the second structure2140 are capable of moving in a horizontal direction. As shown in FIG.21B, the first structure 2120 can move in a direction Z1 and/or thesecond structure 2140 can move in a direction Z2. Either of thestructures 2120 and 2140 can be fixed in place by being mounted to asubstrate, another structure, or the like.

Each structure can include sections of varying arrangement along itsdepth. For example, in the embodiment shown, the first structure 2120includes a set of sections 2180 and the second structure 2140 a set ofsections 2190. Each section of the sets 2180 and 2190 can vary size,being shown with widths of a distance D21, which has a minimumdimension, equal to the MFS. These sections can each have a differentpattern of the arrangement of the vertical layering (e.g. extended andrecessed layers) as desired. By varying the pattern of the layering indifferent sections along the depth of the device, the device is capableof providing improved performance by minimizing the number of extendedsub-gaps and maximizing the number of shortened sub-gaps over themovement of the structures relative to one another.

In other alternate embodiments, the specific horizontal positioning ofthe sub-gaps can vary along each aligned layer (e.g. positioned in parton either of the two structures). In other alternates, the positions ofthe ends of each layer in the device 2100 can vary and are notnecessarily aligned as shown. While in other embodiments the ends of thelayers of the device 2100 can vary in position such that they are notaligned, as shown, aligning the ends 2132 and 2128 and the ends 2143 and2148 provides the benefit of closer structure positioning.

The vertical pattern of the layers in the first and second structures2120 and 2140 as well as the horizontal pattern across the sections 2280and 2290 along the depth, can be any of a variety of arrangements. Forinstance, the same or similar patterns as those used for the layering inthe offset vertical comb actuators described herein (e.g. devices 900,1000, 1200, 1300, 1400, 1500, 1600, 1700, 1800 and 1900), can be appliedto obtain similar improvements in performance.

The device 2100 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

In other embodiments of the horizontal comb actuator, the actuator isnot only patterned in extended (flush) and recessed portions vertically,but is also patterned along its depth. This horizontal patterning allowsfor selective arrangement of the extended and recessed portions toachieve improved performance by minimizing extended sub-gaps andmaximizing shortened sub-gaps during the horizontal movement of thestructures relative to one another (as with layer patterning in thevertical comb actuators, further described herein). The horizontalpatterning used can be any of a variety of different arrangementsdepending on the specific requirements of the particular use. In fact,by horizontally offsetting the two structures, regions of all extendedsections of each structure can be formed to further facilitate operationof the device.

FIG. 22 shows an example of an embodiment of a horizontal actuator withdepth-wise patterning. FIG. 22 showing a top view of the actuator withstructures having depth-wise section patterning. The device 2200includes a first structure 2220, a second structure 2240 and a gap 2260separating them. As can be seen in FIG. 22, depending on the specificembodiment, the first structure 2220 may capable of moving in thedirection of Z1 and/or the second structure 2240 may be capable ofmoving in a direction Z2. Also, either one of the two structures may befixed in place.

The device 2200 can be used in a variety of applications, in at leastone embodiment the device is an actuator, or more specifically ahorizontal comb actuator. The first structure 2220 and the secondstructure 2240 can be fixed and/or movable electrodes.

Like with the vertical actuators described herein, the first structure2220 and the second structure 2240 are fabricated with a series oflayers stacked vertically. The layers can be patterned to have series ofextended and recessed layers. Separating the aligned layers between theelectrodes is a series of sub-gaps, which have a width of the distanceA22 (from a recessed end to a flush end). While the width of thesub-gaps can vary, they are limited to a minimum size of the MFS.However, the minimum separation between the electrodes (an extended endon one structure to an extended end on the other), is a distance B22.

The structures 2220 and 2240 can be fabricated in the position shown;such that they have a horizontal offset a distance E22 as shown. Whilethe about of offset can vary, here the offset E22 is equal to a sectionof a series of sections 2280 and a series of sections 2290.

Along the depth of the first structure 2220 the series of sections 2280includes first sections 2282 and second sections 2284. The width of thesections 2280 is a distance D22, which has a minimum length of the MFS.Depending on the particular embodiment, the pattern of the layering ofeach section can vary. In the embodiment shown, the first and secondstructures have opposite patterns. The section 2280 also includes anoffset section 2286 which made is entirely of extended layers. This isachievable due to a lack of any opposing structure being positionedacross from the section 2286, due to the horizontal offset of thestructures.

Similarly, the series of sections 2290 includes first sections 2292,second sections 2294 and an offset section 2296, which is entirely ofextended layers. The width of the sections 2290 can vary, shown here asthe distance D1, which has a minimum width of the MFS of the device2200.

A benefit provided by the horizontal offset is that as the structuresmove towards each other, the sections 2286 and 2296, which arecompletely of extended end layers, the overall separation of thestructures will decrease. That is, instead of moving towards sectionshaving a pattern of recessed and extended layers (to allow MFS sizedsub-gaps due to opposing structure), the sections move towards sectionswith all extended layer formable from the lack of opposing structure.This results in an overall increase in the performance of the device.

Depending on the embodiment, the pattern of the sections 2280 and 2290along the depth of the first structure 2220 and the second structure2240 can be any of a variety of arrangements. For instance, the same orsimilar patterns as those used for the layering in the offset verticalcomb actuators described herein (e.g. devices 900, 1000, 1200, 1300,1400, 1500, 1600, 1700, 1800 and 1900), can be applied in the offsethorizontal comb actuators to achieve similar improvements inperformance.

It should be clear to one skilled in the art that the device 2200 andits alternate embodiments can be formed by embodiments of thefabrication methods set forth herein.

Capacitance Type Actuator Embodiments

Some embodiments of applicants' invention provide a capacitance typeactuator (CTA). In a capacitance actuator, unlike the vertical anddepth-wise movements of the VCA and the HCA respectfully, where thestructures move relative to each other while maintaining a substantiallyconstant separation, the two structures of a CTA move directly towardseach other as a result of a force generated by a capacitance chargeplaced on the structures. An embodiment of a capacitance actuator isshown in FIG. 23.

A device 2300 includes a first structure 2320, a second structure 2340and a gap 2360 separating the structures. Depending on the embodiment,either the first structure 2320 and/or the second structure 2340 canmove horizontally towards and away from each other. The first structure2320 may be capable of moving in a direction Y1 and/or the secondelectrode may be able to move in a direction Y2.

The device 2300 can be used in a variety of applications, in at leastone embodiment, the device 2300 is an actuator, or more specifically acapacitance type actuator. The first structure 2320 and the secondstructure 2340 can be fixed and/or movable electrodes.

The first structure 2320 includes a series of layers 2322. The layers2322 are formed into sets of extended layers 2326 with ends 2328 and aset of recessed layers 2330 with ends 2332. Likewise, the secondstructure 2340 includes a series of layers 2342. The layers 2342 areformed into sets of extended layers 2346 with ends 2348 and a set ofrecessed layers 2350 with ends 2352. Set between the extended sets 2326and the recessed sets 2350 are sub-gaps 2362 and between the extendedportions 2346 and the recessed portions 2330 are sub-gaps 2364.

To facilitate movement of one or both of the structures and minimize theseparations there between, the extended layers and the recessed layersof both structures are substantially aligned with one other. That is,the recessed areas are capable of receiving the extended areas. To avoidcontact or interference between the two structures, the sets of recessedlayers 2330 and 2350 can be made larger than the sets of the extendedlayers 2326 and 2346. As shown, in this embodiment the sets of recessedlayers are two layers wider than the sets of extended layers.

At an initial position (as shown), the distance from an set of extendedlayers on one structure to a corresponding set of recessed layers on theopposite structure is a distance A23, which is limited to a minimumlength of the MFS. The distance between sets of extended layers of bothstructures is a distance B23, which depending on the specificembodiment, can be substantially less than the MFS.

The number of layers 2322 and 2342 used to form the structures can varydepending on the embodiment. While in the embodiment shown in FIG. 23,each extended and recessed set of layers is made of several of layers,less or more layers can be used. However, use of several layers for eachset allows the recessed layers sets to be formed larger than theextended layer sets that they receive.

The device 2300 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

Serrated Actuator Embodiments

Other embodiments of the invention include an actuator having serratededges on the structures. The serrated edges are positioned opposing eachother to form a zigzagged shaped gap between the structures. Theserrated edge structures can be used in a variety of actuators includingvertical comb actuators, horizontal comb actuators and capacitance typeactuators. Depending on the particular embodiment, by employing serratededges on the structures, the actuator is capable of having a reducedoverall offset, and therefore, increased performance.

One embodiment of a device having serrated edges is set forth in the topview of FIG. 24, wherein a device 2400 includes a first structure 2420,a second structure 2440, and separating them, a zigzag shaped gap 2460.The first structure 2420 includes recessed regions 2482 and extendedregions 2484. The second structure 2440 includes extended regions 2492and recessed regions 2494. The recessed regions 2482 being laterallyaligned with the extended regions 2492 and the extended regions 2484aligned with the recessed regions 2494.

The device 2400 can be used in a variety of applications, in at leastone embodiment, the device 2400 is an actuator, such as a VCA, HCA or aCTA. The first structure 2420 and the second structure 2440 can be fixedand/or movable electrodes.

As shown, the gap 2460 has a width of a distance A24. While the size ofthe gap 2460 can vary, due to the inherent manufacturing limitations,the minimum width of a sub-gap is the MFS of the device 2400. In itsinitial position, the gap 2460 has a series of sub-gaps including firstsub-gaps 2462 positioned between the recessed regions 2482 and theextended regions 2492 and the second sub-gaps 2464 between the extendedregions 2484 and the recessed regions 2494.

While the embodiment shown in FIG. 24 has the extended regions alignedwith the recessed regions, in other embodiments the device can have theextended regions on one structure aligned with extended regions on theother structure, and recessed regions aligned with other recessedregions. This can be achieved by either further widening the gap betweenthe electrodes to allow the separation between the extended regions tobe no less than the MFS or by moving the electrodes in a depth-wisedirection (within the plane shown) from an initial position, such asthat shown in FIG. 24.

To further reduce the separation between the structures, an embodimentof the invention utilizes staggered horizontally aligned layers withserrated edges. Even though the separation on each layer is at least theMFS, the extended portions of each electrode can be positioned to have aseparation significantly less than the MFS. This provides for anincrease in the performance of the actuator, as compared to that of anactuator having non-staggered layering.

FIGS. 25A and 25B show an embodiment of the Applicants' invention,wherein a device 2500 has structures with staggered layers and serratededges, such that the structures are capable of being separated by adistance that is less than the MFS. A first structure 2520 is separatedby a gap 2560 from a second structure 2540. Depending on the embodiment,the first structure 2520 and/or the second electrode 2540 can be capableof moving in variety of directions, including vertical (X1 and/or X2),and horizontal (Y1 and/or Y2), as shown (the structures may also move inthe depth-wise direction, Z1 and/or Z2, provided sufficient clearanceexists). Also, either structure 2520 or 2540 may be stationary.

The device 2500 can be used in a variety of applications, in at leastone embodiment the device 2500 is an actuator, including a VCA, HCA or aCTA. The first structure 2520 and the second structure 2540 can be fixedand/or movable electrodes.

The first structure 2520 and the second structure 2540 have alignedlayers which are separated by staggered gaps and that have ends whichare serrated in a depth-wise direction (Z direction). The firststructure 2520 has a set of layers 2522 which alternate between recessedlayers 2526 with ends 2528 and extended layers 2530 with ends 2532.Likewise, the second structure 2540 includes a series of layers 2542with extended layers 2546 having ends 2548 and recessed layers 2550 withends 2552. Along the depth of the device 2500, the extended layers 2530have extended regions 2584 and recessed regions 2582, and the extendedlayers 2546 have extended regions 2592 and recessed regions 2594.

The gap 2560 is not only in a zigzag configuration along the depth ofthe device 2500, but also in a staggered arrangement along the verticaldirection (X direction). Along each layer of the device 2500, the gap2560 includes sub-gaps 2562, positioned between the ends 2528 and 2548,and sub-gaps 2564, positioned between the ends 2532 and 2552. As shown,the width of each sub-gap is a distance A25 which, depending on theembodiment can vary, but is limited to a minimum of the MFS. Incontrast, the distance between the extended layers 2530 and the extendedlayers 2546 is a distance B25, which is capable of being a distance lessthan the MFS.

Alternate embodiments include using vertical and horizontal offsets ofthe first and second structures in their initial construction positions,with the structures being able to be moved to non-offset positions withless overall separation between the structures. Further, the patterningof the layering can be arranged so to facilitate moving the structuresfrom an initial offset position to a more aligned position.

The devices 2400 and 2500 and their alternate embodiments can be formedby embodiments of the fabrication methods set forth herein.

Filter Apparatus Embodiments

In other embodiments of the invention the apparatuses and methods employstaggered or varied layer patterning to define elements or featureswhich are capable of being sized less than the MFS. By utilizingmaterial layers with different patterns of openings, or gaps, which areplaced over each other, a separate pattern of openings, or gaps, whichare defined at the intersection of the layers, can be formed. That is,one or more openings in adjacent layers can be positioned to overlap,such that one or more smaller sized opening(s) are obtained at theoverlap. Because the size of the defined openings are dependent only onthe amount of overlap between the openings, and not the size of theparticular openings in the layers, the openings may have dimensionswhich are less than the manufacturing limits of the openings in thepatterned layers. As detailed herein, examples include deposition ofabutting or closely spaced layers, having differing patterns ofopenings, which together define a composite pattern of holes sizedsmaller than the MFS. Applications of these embodiments can include thefabrication of precise micro-filters/screens and/or nozzles.

As shown in FIGS. 26-28, one embodiment of the invention is an apparatusand fabrication method of a layered device having elements or featuresdefined at the intersection of the layers. More specifically, theembodiments include a multi-layered structure that has one or moreopenings or gaps defined in adjacent layers, which are positioned tooverlap to define other opening(s) or gap(s) between the layers at theoverlap.

FIG. 26A shows a first layer 2610 of a device 2600 that includes a frame2612 which defines a first opening or gap 2614 therein. The firstopening 2614 passes through the first layer 2610, which, depending onthe particular application, is capable of allowing the flow of a fluid,gas, particles or the like through the first layer 2610. The opening2614 is defined with corners 2616 and walls 2618 about it. The specificsize and shape of the opening 2614 can vary. The inherent limitations ofthe fabrication of the layer 2610 limits the minimum size of anydimension of the opening 2614 to the MFS of the device 2600. The shapeof the opening 2614 can be any of a variety of geometric shapesincluding squares and rectangles. In the particular embodiment shown,the opening 2614 is square with the dimensions of a width A26 and awidth A26.

The second layer 2620 has a frame 2622 that defines an opening or gap2624, as shown in FIG. 26B. The opening 2624 passes through the secondlayer 2620, which is capable of allowing the flow of a fluid, gas,particles or the like. The opening 2624 is defined with corners 2626 andwalls 2628. The specific size and shape of the opening 2624 can vary,but as with the opening 2614 the opening 2624 is also limited to minimumdimensions of the MFS of the device 2600. The shape of the opening 1624can be a variety of different geometric shapes (square, rectangular,etc.). Here the opening 2624 is square with the dimensions of a widthA26 and a width A26.

The first opening 2614 and the second opening 2624 together define asmaller third opening or gap 2630. The overlapping of the openings 2614and 2624 provide the defined opening 2630 at the interface of the twolayers. The defined opening 2630 includes a corner 2616 and walls 2618of the opening 2614, and a corner 2626 and walls 2628 from the opening2624. With the size of the defined opening 2630 being dependent onlyupon the portion of overlap between the openings 2614 and 2624, the sizeof the opening 2630 is independent of the limitation in minimum featuresize inherent with the openings 2614 and 2624.

As a result, the opening 2630 is not specifically limited in minimumsize to the MFS of the device 2600, as is otherwise the situation withany feature constructed with in a single material layer. As shown in theembodiment of FIG. 26B, the defined opening 2630 is square with thedimensions of a width B26 and a width B26. That is, the width B26 iscapable of being made with less than the MFS. Other shapes (e.g.rectangles, triangles, etc.) and dimensions of the defined opening 2630are possible in other embodiments of the invention.

The device 2600 can be used in a variety of applications, in at leastone embodiment, the device 2600 is on its own or part of a screen, whichcan be employed for operations such as filtering or the like.

Filter Fabrication Method Embodiments

Some embodiments of Applicants' invention provide methods of fabricatingpatterned layered structures to define elements capable of being sizedless than the MFS, such as the device 2600. Generally, the fabricationmethods include depositing a first layer with a first element (e.g. anopening, pore, space, and gap), depositing a second layer with a secondelement positioned so to define a third element at an intersection of,or in between, the first layer and the second layer.

As shown in FIG. 27, one embodiment of a method for fabricating a filterhaving a minimum feature size 2700 includes the processes of providing adeposition surface 2710, depositing a first layer onto the depositionsurface, wherein the first layer has a first opening sized at least aslarge as the minimum feature size 2720, depositing a second layer ontothe first layer to form a layered structure, wherein the second layerhas a second opening sized at least as large as the minimum featuresize, wherein the second opening is positioned overlapping the firstopening to define a third opening between the first layer and the secondlayer, and wherein the third opening is sized less than the minimumfeature size 2730 and releasing the layered structure 2740.

As will be detailed herein, the structures obtainable by operation ofthe method 2700 can be of a variety of different embodiments, examplesof which are shown in FIGS. 26A-26B and 28A-26E.

During the process of providing a deposition surface 2710, as shown inFIG. 27, a suitable surface for the later deposition of the first layeris obtained. The deposition surface can be located on any of severaldifferent types of structures including, a substrate and a layered orformed structural or sacrificial element. In certain embodiments whereina fluid or gas is to flow through the openings in the device, asacrificial material can be used for the deposition surface to providefor a later pathway of the fluid or gas flow, such as shown in FIG. 28A.In such embodiments the process 2710 can include the steps of providinga substrate, depositing at least one layer of sacrificial material uponthe substrate, and forming a deposition surface on the sacrificialmaterial.

The element on which the deposition surface is provided can be of any ofa variety of suitable materials formable to have a surface smooth enoughto allow for layer deposition. Such suitable materials can includesilicon, glass, plastic, or a metal (e.g. nickel, copper, silver, gold,etc.). The deposition of materials can be done by any of a variety ofprocesses well known in the art. Likewise, the surface provided can beformed through any of a variety of methods well known in the artincluding etching (wet or dry), milling, lapping, molding, extrusion andthe like.

In some embodiments, the process of providing a surface can also includeapplying a seed layer on the structure in order to facilitate laterlayer deposition. For instance, if the material of the structure used isnot sufficiently conductive (e.g. plastic or glass) to allowelectrodeposition techniques to be employed for layer deposition, then aseed layer of conductive material can be used.

One embodiment of a structure obtainable by operation of the process ofproviding a deposition surface 2710 is shown in FIG. 28A. A structure2600 a includes a substrate 2602, layers of sacrificial material 2604and a deposition surface 1606.

Another process of the method 2700 is depositing a first layer onto thedeposition surface, wherein the first layer has a first opening sized atleast as large as the minimum feature size 2720, as shown in FIG. 27.Depending on the embodiment, the process 2720 may further include thesteps of depositing a first layer of material defining the firstopening, depositing a sacrificial material to provide a continuouslayer, and forming a deposition surface.

FIGS. 26A and 28B set forth some embodiments of structures formable bythe operations of the process 2720. As shown in FIG. 28B, the step ofdepositing a first layer of material can provide a device 2600 b withthe first layer 2610 deposited over the deposition surface 2606. Thefirst layer 2610 has the frame 2612 with the first opening 2614 havingwalls 2618. The material of the first layer 2610 can be deposited to athickness greater that the final desired thickness of the first layer2610, as any additional material can be removed during the later step offorming a deposition surface. In this embodiment, the first layer 2610is a structural material. The specific material used for the structuralmaterial can vary (including gold, silver, nickel, copper, and thelike), in some embodiments the material is a nickel.

For the selective deposition of the first layer 2610, as shown in FIGS.26A and 28B, any of the herein described masks and masking techniques(e.g. INSTANT MASK™, MOA, AIM, ACC, methods detailed in the '630 patentand '637 patent disclosures), can be employed. Deposition of thematerial of the first layer 2610 can be performed by any of a variety ofelectrodeposition methods including the electrochemical fabricationmethods described herein. Then the mask is removed by processesassociated with the type of mask used.

The use of a mask to deposit the first layer 2610 limits the minimumobtainable size of any feature or element defined on the layer 2610 tothe minimum feature size (MFS) of particular the mask used. The specificdimension of the MFS is dependent on the type of mask and maskingtechnique used. The MFS is a direct function of smallest feature whichcan be defined during the fabrication of the mask itself. As a result,the minimum dimensions of the opening 2614 defined in the frame 2612 isthe MFS of the process used.

Depositing a sacrificial material to provide a continuous layer isanother possible step in the process 2720. The deposition of thesacrificial material allows later shaping and sizing of the first layerby covering the opening and areas about the frame 2612, such that acontinuous material layer is formed. Such a continuous layer allowsmethods such as planarization to be employed.

The specific material used as the sacrificial material can be any of avariety of suitable materials (including gold, silver, nickel, copper,and the like), in some embodiments sacrificial material is a silver. Thesacrificial material can be deposited by any of a variety of methodsincluding a blanket electrodeposition. The blanket deposition can beachieved by electroplating from an anode (not shown), composed of thesacrificial material, through an appropriate plating solution (notshown), and to the cathode, which here is the frame 2612 (or at leastthe exposed surface thereof).

It should be noted that in alternate embodiments of method the materialof the frame 2612 is a sacrificial material instead of a structuralmaterial, and sacrificial regions are of a structural material insteadof a sacrificial material.

Next, the step of forming a deposition surface can be performed tocomplete the process 2720. An embodiment of a structure 2600 cobtainable by operation of the sacrificial material deposition step andthe deposition surface forming step, includes the structure shown inFIG. 28C. As shown, a sacrificial material has been deposited about theframe 2612 and in the first opening 2614 such that a continuous layer2613 was formed (as detailed above). A deposition surface 2617 is formedacross the structure 2600 c to be sufficiently smooth to allowadditional material deposition.

During the deposition surface forming step the continuous layer ofmaterial formed by the sacrificial material deposition step, is sizedand shaped by removing the excess portions of the deposited layermaterial (e.g. the first and second material), to achieve a layer 2613of a desired thickness and surface, as shown in FIG. 28C.

The process of sizing and shaping the deposited material to achieve thelayer 2613 can be achieved by any of a variety of methods well known inthe art including, etching (wet or dry), milling, lapping and the like.One such method is planarizing by a lapping operation. During lapping,material is removed by moving an abrasive element over, or relative to,the surface of the structure, until a desired thickness of the layer2613 and smoothness of the surface 2617 is achieved.

Another process in the fabrication method 2700 is depositing a secondlayer onto the first layer to form a layered structure, wherein thesecond layer has a second opening sized at least as large as the minimumfeature size, wherein the second opening is positioned overlapping thefirst opening to define a third opening between the first layer and thesecond layer, and wherein the third opening is sized less than theminimum feature size 2730, as shown in FIG. 27. During this process anopening is constructed in the second layer such that it overlaps withthe opening of the first layer so that a smaller opening is definedbetween the two layers.

The process 2730 can further include the step of depositing a secondlayer of material with an opening defined therein. Additional optionalsteps can include depositing a sacrificial material to provide acontinuous layer, and forming a deposition surface. Such steps can beemployed if a layer thickness less than that initially deposited isdesired and if additional layers are to be deposited over the secondlayer.

FIGS. 26B and 28D show an embodiment of a device 2600 d having a layer2620 which can be formed by operation of the process 2730. The secondlayer 2620 has the frame 2622 with the second opening 2624 having walls2628.

As noted, the material of the second layer 2620 can be deposited to athickness greater than desired and later sized in a forming step. Thespecific material used for the frame 2622 can any of a variety (e.g.gold, silver, nickel, copper, and the like), in certain embodiments thematerial is a nickel.

For the selective deposition of the second layer 2620, any of a varietyof described masks and masking techniques (e.g. INSTANT MASK™, MOA, AIM,ACC, methods detailed in the '630 patent and '637 patent disclosures),can be employed. Deposition of the material can be performed by any of avariety of electrodeposition methods described herein. The mask isremoved by a process appropriate to the type of mask used.

Like with the deposition of the first layer 2610, during the depositionof the second layer 2620, the use of a mask limits the minimumobtainable size of any feature or element defined on the layer 2620 tothe minimum feature size (MFS) of the particular mask used. The specificdimension of the MFS is dependent on the type of mask and maskingtechnique used. The MFS is a direct function of smallest feature whichcan be defined during the fabrication of the mask itself. As a resultthe minimum dimensions of the second opening 2624 defined in thestructure 2622 is the MFS of the process used.

However, unlike the openings 2614 and 2624, the third opening 2630(which is defined by these openings) is not limited in its dimensions tothe MFS. The dimensions of the opening 2630 are instead determined bythe amount of overlap of the openings 2614 and 2624.

Depositing a sacrificial material to provide a continuous layer allowslater shaping and sizing of the second layer 2620. This is achieved byfilling the opening and areas about the frame 2622 such that acontinuous material layer is formed, so that methods such asplanarization to be employed to size and shape the layer.

The sacrificial material can be any of a variety of suitable materials(e.g. gold, silver, nickel, copper, and the like), with some embodimentshaving sacrificial material as a silver. Deposition of the sacrificialmaterial can by any of a variety of methods (e.g. blanketelectrodeposition).

The step of forming a deposition surface can be used to size the layer2620 and smooth the surface for any additional material deposition. Thiscan be achieved by any of a variety of methods well known in the artincluding, etching (wet or dry), milling, lapping and the like. Onemethod is planarizing by a lapping operation, where material is removedby moving an abrasive element over, or relative to, the surface of thestructure to reach the desired thickness and smoothness.

The next process in the fabrication method 2700 is releasing the layeredstructure 2740. During this process by removing the sacrificial materialthe structure constructed during the deposition is released. Thesacrificial material can be removed by any of a variety of methodsincluding using an etching process. Useable etching processes includeapplying a chemical etchant which is sufficiently reactive with thesacrificial material to dissolve it. The etchant used should besubstantially non-reactive with the structural material to prevent, orproperly limit, any etching of the structural material.

FIG. 28E shows an embodiment of a device 2600 e which can be fabricatedafter performing the process of releasing the structure 2740. The device2600 e includes the third opening 2630 which is defined by a combinationof the first opening 2614 of the first layer 2610 and the second opening2624 of the second layer 2620. The third opening 2630 is defined by thewalls 2618 and the walls 2628. With the size of the defined opening 2630being is dependent only on the portion of overlap between the openings2614 and 2624, the size of the third opening 2632 is independent of theany limitations in the minimum size of either opening 2614 or opening2624.

Filter with Array of Pores Apparatus Embodiments

Another embodiment of the invention includes an apparatus andfabrication method for a layered structure which is configured to defineelements or features between the layers, is shown in FIG. 29C and thecross-section in FIG. 30C. Specifically, shown is a structure or devicewhich employs staggered or varied layer patterning to define a screen,filter or grid 2930 having a series of defined or third pores, openingsor gaps 2832. The screen 2930 is formed from a first patterned layer2910, as shown in FIG. 29A and the cross-section in FIG. 30A (shownduring fabrication, as detailed herein), and a second patterned layer2920, as set forth in FIG. 29B and the cross-section in FIG. 30B (alsoshown during fabrication, as detailed herein).

FIGS. 29A and 30A show the first or base patterned layer 2910 with afirst or base structural lattice, grid or frame 2912 which is shaped todefine a pattern of first or base pores, openings or gaps 2914. Thepores 2914 pass through the first layer 2910, which, depending on theparticular application, can allow the flow of a fluid, gas or a seriesof particles through the first layer 2910. The pores 2914 are definedwith corners 2916 and sides or walls 2918.

The specific size and shape of each pore 2914 can vary, depending on thedesired size, pattern and number of the defined pores 2932 in the screen2930. The shape of the first pores 2914 can be any of a variety ofgeometric shapes including squares (as shown in FIG. 29A) andrectangles. In the same manner, the size and shape of the firststructural grid 2912 defining the first pores 2914 can vary, not only todefine the first pores 2914, but also to space and position them.Because of the inherent limitation of the fabrication of the first layer2910, the minimum size of any dimension of either the first pores 2914and/or of the width of the first grid 2912 is the MFS. In the embodimentshown, the first pores 2914 have widths A29 and the first grid 2912 hasdimensions of B29. While the specific lengths of the distances A29 andB29 can vary depending on the particular use, they have a minimum lengthof the MFS.

The second patterned layer 2920 is shown in FIGS. 29B and 30B. Thesecond layer 2920 is patterned in a second structural grid, lattice orframe 2922 that defines a series of second pores, openings or gaps 2924.The second pores 2924 are defined with corners 2925. The second openings2924 include center pores 2926 and edge pores 2928. The second pores2924 pass through the second layer 2920, such that the second pores 2924are capable (depending on the embodiment) of allowing the passage of afluid, gas, particles or the like.

The particular size and shape of the second grid 2922 is variable to notonly define the size and shape of the second pores 2924, but also tospace and position them. The shape of the pores 2924 can also be of anyof a variety of sizes and shapes. Like with the first grid 2912, thesize and an arrangement of the second layer 2920 is limited to a minimumsize of the MFS. That is, the width of the second grid 2922 and/or thewidth of the second pores 2924, must be a least as wide as the MFS. Theembodiment shown here has the second pores 2924 with widths C29 and thesecond grid 2922 with dimensions of D29. While the specific lengths ofthe distances C29 and C29 can vary, the minimum length of both is theMFS.

FIGS. 29C and 30C show a structure having a pattern of pores defined bya combination of the first layer 2910 and the second layer 2920.Specifically, as shown, the structure 2930 includes the second layer2920 positioned over the first layer 2910, such that a series of definedpores 2932 are defined between the two layers. In so doing, the definedpores 2932, being a composite of portions of two separate layers, arenot specifically limited in its minimum size as is the case with anycomponent or element defined in a single layer. Therefore, the size ofthe pores 2932 are capable of being sized less than the MFS for theprocesses used to fabricate the first patterned layer 2910 and thesecond patterned layer 2920.

The defined pores 2932 are formed at the overlapping of the first pores2914 of the first layer 2910 and the second pores 2924 of the secondlayer 2920. The pores 2932 include a corner 2916 from the first layer2910 and a corner 2925 from the second layer 2920. With the definedpores 2932 being rectangular in shape, two sizes adjacent to the corners2916 are portions of the pores 2914 and two sides adjacent to thecorners 2925 are portions of the pores 2924.

The size of the defined pores s 2932 are dependent only of thedifference of the sizes of the second grid 2922 and the first pores2914, and therefore independent of the MFS limitations of thefabrication of elements in a single layer. With the width of the secondgrid 2922 being sized less than the corresponding width of the firstpores 2914, the pores 2932 are defined at the overlap. The defined pores2932 therefore can have dimensions less than the MFS. In the embodimentshown in FIGS. 29C and 30C, the widths of the defined pores 2932 is adistance E29, which can vary in size, but is not limited to by the MFSof the layers 2910 and 2920.

While the size of the defined pores 2932 are independent of the MFSlimits of the pores of each layer, the positioning and density of thedefined pores 2932 are directly related to the MFS. Namely, the definedpores 2932 are each separated by distances which depend on the MFS andas shown cannot be less than the MFS.

These embodiments of the invention provide the ability to formstructures such as screens, filters, grids, or the like with pores oropenings significantly smaller than the pores formed in a singlematerial layer.

Filter with Array of Pores Fabrication Method Embodiments

Some embodiments of the invention include an embodiment of a method forfabricating an apparatus having a grid or screen of openings capable ofbeing sized less than the MFS. The method of fabrication in generalinvolves initially the deposition of a first layer that has a firstarray of openings, and then the deposition of a second layer with asecond array of openings arranged to define a composite array ofopenings at the intersection of the first layer and the second layer.

One embodiment of the method is set forth in FIG. 31. As shown, a methodfor fabricating a filter having a minimum feature size 3100 includes theprocesses of providing a deposition surface 3110, depositing a firstlayer onto the deposition surface, wherein the first layer has a firstarray of pores, and wherein each pore of the first array of pores issized at least as large as the minimum feature size 3120, depositing asecond layer onto the first layer to form a layered structure, whereinthe second layer has a second array of pores, wherein each pore of thesecond array of pores is sized at least as large as the minimum featuresize, wherein the second array of pores is positioned overlapping thefirst array of pores to define a third array of pores between the firstlayer and the second layer, and wherein each pore of the third array ofpores is sized less than the minimum feature size 3130; and releasingthe layered structure 3140.

As will be detailed herein, the structures obtainable by operation ofthe method 3100 can be of a variety of different embodiments, examplesof which are shown in FIGS. 29A-29C and 30A-30C as described herein.

The process of providing a deposition surface 3110 is similar to theprocess 2710 of the method 2700, as described herein (shown in FIG. 27).That is, the structure provided includes a deposition surface which issuitable (e.g. sufficiently smooth) for layer deposition, and thestructure it can any of several different types. A sacrificial materialcan be used as the structure for forming the deposition surface, suchthat pathway for the flow of the fluid or gas can be created after thereleasing process 3140. The deposition surface can be provided on any ofa variety of suitable materials, including silicon, glass, plastic, or ametal (e.g. nickel, copper, silver, gold, etc.). The deposition of suchmaterials and forming of the surface, can be done by any of a variety ofprocesses well known in the art. The process of providing a depositionstructure 3110 can also include applying a seed layer to facilitatelater layer deposition (as detailed herein). One embodiment of adeposition structure is shown in FIG. 30A, wherein a substrate 2902 anda set of sacrificial layers 2904 are a deposition structure with adeposition surface 2906.

Another process of the method 3100 is depositing a first layer onto thedeposition surface 3120, as set forth in FIG. 31. This process canfurther include the steps of depositing a first layer of material withan array of pores or openings, depositing a sacrificial material toprovide a continuous layer, and forming a deposition surface.

FIGS. 29A and 30A show an embodiment of a structure formable by theoperations of the deposition step of the process 3120. The first layer2910 has the first grid 2912 defining an array of pores or openings2914. The material of the first layer 2910 can be deposited to athickness greater that the desired thickness of the first layer 2910, asany additional material can be removed during the forming step of theprocess. The specific material used for the first layer 2910 can vary(including gold, silver, nickel, copper, and the like), in someembodiments the material is a nickel.

For the selective deposition of the first layer 2910, as shown in FIGS.29A and 30A, any of the herein described masks and masking techniques(e.g. INSTANT MASK™, MOA, AIM, ACC, methods detailed in the '630 patentand '637 patent disclosures), can be employed. Deposition of thematerial of the first layer 2910 can be performed by any of a variety ofelectrodeposition methods including the electrochemical fabricationmethods described herein. Then the mask is removed by any processassociated with the type of mask used.

The use of a mask to deposit the first layer 2910 limits the minimumobtainable size of any feature or element on the layer 2910 to the MFSof the mask used. As a result the minimum dimensions which can beachieved with the first grid 2912 and/or the openings 2914 is the MFS.

Another step in the process 3120 is depositing a sacrificial material toprovide a continuous layer. A sacrificial material can be depositedabout the first grid 2912 and in the pores 2914, to form the continuouslayer of material. By creating a continuous layer of material, thedeposition of the sacrificial material facilitates later shaping andsizing (e.g. planarization) of the first layer 2910. The sacrificialmaterial can be a variety of materials (including gold, silver, nickel,copper, and the like), in some embodiments it is a silver. Thesacrificial material can be deposited by any of a variety of methodsincluding a blanket electrodeposition. In alternate embodiments of themethod, the material of the structural regions can be a sacrificialmaterial and the sacrificial regions can be a structural material.

Next, the step of forming a deposition surface can be performed in theprocess 3120. During the forming step the continuous layer of materialformed during the deposition step, is sized and shaped by removing theexcess portions of the deposited layer material, to achieve a layer of adesired thickness and surface. The process of sizing and shaping thedeposited material can be achieved by any of a variety of methods wellknown in the art including, etching (wet or dry), milling, lapping andthe like. One such method is planarizing by a lapping operation, asdetailed herein.

Another process in the fabrication method 3100 is depositing a secondlayer onto the first layer to form a layered structure 3130, as setforth in FIG. 31. During this process a second array of pores isconstructed and positioned in the second layer, such that it there is anoverlap with the first array of pores. This overlap defines a compositearray of smaller pores at the intersection of the first and secondlayers. Since the size of the pores in the composite array are dependentonly on the amount of overlap and not on the size of features in any onelayer, the composite grid can have pores sized less than the MFS of thefirst and second layers.

The process 3130 can further include the additional steps of depositinga sacrificial material to provide a continuous layer, and forming adeposition surface. Such additional steps can be employed in embodimentswhere the thickness of the material forming the second layer asinitially deposited is thicker than the desired thickness of the secondlayer, and the second layer must be sized, or if additional layers areto be later deposited over the second layer.

FIGS. 29B and 30B show an embodiment of a second layer 2920 which can beformed by operation of the process 3130. The second layer 2920 has thesecond grid 2922 with the array of pores 2924, as described herein. Thematerial deposited to form the second grid 2922 can any of a variety(e.g. gold, silver, nickel, copper, and the like), in certainembodiments the material is a nickel.

For the selective deposition of the second layer 2920, any of a varietyof described masks and masking techniques (e.g. INSTANT MASK™, MOA, AIM,ACC, methods detailed in the '630 patent and '637 patent disclosures),can be employed. Deposition of the material can be performed by any of avariety of electrodeposition methods described herein. The mask isremoved by a process appropriate to the type of mask used.

Like with the deposition of the first layer 2910, during the depositionof the second layer 2920, the use of a mask limits the minimumobtainable size of any feature or element defined on the layer 2920 tothe MFS of the mask used. As a result the minimum dimensions of thepores 2924 and the grid 2922 is the MFS.

However, unlike the pores 2914 and 2924, the defined pores 2932 are notlimited in its dimensions to the MFS. The dimensions of the definedpores 2932 are instead determined by the overlap of the pores 2914 and2924.

Depositing a sacrificial material to provide a continuous layer allowslater shaping and sizing of the second layer 2920. This is achieved byfilling the openings 2924 and areas about the structure 2922, such thata continuous material layer is formed, so that methods such asplanarization to be employed to size and shape the layer.

The sacrificial material can be any of a variety of suitable materials(e.g. gold, silver, nickel, copper, and the like), with some embodimentshaving sacrificial material as a silver. Deposition of the sacrificialmaterial can by any of a variety of methods (e.g. blanketelectrodeposition).

The step of forming a deposition surface can be used to size the layer2920 and smooth the surface for any additional layer materialdeposition. This can be achieved by any of a variety of methods wellknown in the art including, etching (wet or dry), milling, lapping andthe like. One method is planarizing by a lapping operation, as describedherein.

The next process in the fabrication method 3100 is releasing the layeredstructure 3140. During this process, by removing the sacrificialmaterial within the structure which has been constructed during theoperation of the process of the fabrication method, the device isreleased. Release of the device clears the pores in the device of thesacrificial material for the flow of a fluid, gas, particles, or thelike, to pass through the pores.

The sacrificial material can be removed by any of a variety of methodsincluding using an etching process. Useable etching processes includeapplying a chemical etchant which is sufficiently reactive with thesacrificial material to dissolve it. The etchant used should besubstantially non-reactive with the structural material to prevent, orproperly limit, any etching of the structural material. FIGS. 29C and30C show an embodiment of a device 2930 which can be fabricated afterperforming the process of releasing the structure 3140. The device 2930includes the grid of defined pores 2932, which are defined by acombination of the first pores 2914 of the first layer 2910 and thesecond pores 2924 of the second layer 2920.

Filter with Connecting Passage Embodiments

Other embodiments of the apparatus of the invention include deviceshaving at least one passage through them, where the minimum size of thepassage is defined by the thickness of a layer of the device. The deviceincludes at least one connecting or spacing layer that, in conjunctionwith the structure of the surrounding layers, can function as filterpore or opening to restrict passage of particles of a fluid or gas goingthrough the device. That is, the passage can restrict the flow ofparticles to allow passage of only those sized smaller than thethickness of the connecting layer. As a result, the minimum dimension ofthe passage is a function of the minimum thickness of the connectinglayer and not of the MFS of the layers. With the minimum layer thicknessbeing less than the MFS, this embodiment allows production of passagessized smaller than the MFS.

In some embodiments, the device includes offset or staggered apertures(or openings) in the external layers which are connected to each otherby an open section of a connecting layer positioned between the externallayers. Still other embodiments include a series or an array ofconnecting layer passages through the device, to form a screen or gridwhich can function as a filter.

An advantage provided by these embodiments is that the passage can beconfigured to have a low probability of clogging or otherwise becomingblocked with particles passing through it. This is achievable byarranging the passage to have a relatively small dimension (e.g. theconnecting layer thickness) and a relatively large dimension defining across-section to the flow direction. This can also provide the advantagethat the particles flowing through the passage that are not equiaxed,will tend to rotate so as to align themselves so that the particles canenter the passage. Another advantage is that with more than one passage,the passages can be arranged to specifically position areas of inflowand/or outflow from the devices. By so arranging the areas inflow andoutflow, regions of flow restriction, turbulence or stagnation, atlocations upstream or downstream of the device can be reduced oreliminated.

An embodiment of a device with a passage through a connecting or spacinglayer is shown in FIGS. 32A and 32B. As shown, a device 3200 includes afirst layer 3210, a second layer 3220, a third layer 3230 and a passage3240 there through.

As shown in FIG. 32A, the first layer 3210 is an external layer and hasa frame structure 3212 defining an aperture or opening 3214. Likewise,the third layer 3230 is an external layer and has a frame structure 3232which defines an aperture or opening 3234. While the size and shape ofthe openings in the layers can vary, in the embodiment shown, theapertures 3214 and 3234 are square and have widths of distances A32. Theapertures 3214 and 3234 are offset or staggered from each other suchthat they are not positioned over each other. This offset of theapertures allows a connection between the apertures 3214 and 3234 to bedefined in the second layer 3220, such that the passage 3240 isrestricted to the dimension of the thickness of the second layer 3220.

The second layer 3220 includes a frame structure 3222 which defines aconnecting opening 3224 that is positioned to connect the apertures 3214and 3234. The connecting opening 3224 includes a center section 3226positioned between the apertures 3214 and 3234 and the frames 3212 and3234. The passage 3240 includes the section 3226 and the apertures 3214and 3234. In this embodiment, at a cross-section across the flowdirection through the center section 3226, the dimensions are a distanceB32 and a distance A32. The distance B32 is equal to the thickness ofthe second layer 3220 as shown in FIG. 32A. The distance A32 is along adepth-wise direction of the section 3226, as shown in FIG. 32B. Thesecond layer thickness B32 can vary depending on the specific embodimentof the device 3200, for example in some embodiments the thickness isbetween about 1 μm and about 20 μm.

The flow-wise cross-section (e.g. layer thickness B32 and the depth-wiselength A32) of the center section 3226 can be set to match the desiredmaximum particle size allowed to pass through the passage 3240. Thisallows the passage to be configured to match the specific restriction orfiltration requirements for the particular use of the device 3200. Theminimum achievable cross-section for the section 3226 depends on theminimum obtainable dimensions for the depth-wise length A32 and thelayer thickness B32. Since the depth-wise thickness A32 is in the planeof the layer 3220, it is limited to a minimum size equal to the MFS ofthe layer 3220. In some embodiments the MFS is about 40 μm while inother embodiments it may be as low as 10 μm, 5 μm or even less. However,since the thickness B32 is not in the plane of the layer, it is limitedto a minimum size by the minimum layer thickness. In some embodiments ofthe invention the minimum layer thickness is about 2 μm.

In embodiments where the layer thickness B32 is less than the depth-wiselength A32, the thickness B32 is the minimum dimension of the passage3240. With the length A32 substantially greater than the thickness B32,the passage 3240 is capable of providing a low probability of cloggingor otherwise becoming blocked with particles passing through it. Also,in this configuration, the particles flowing through the passage 3240that are not equiaxed, will tend to rotate so as to align themselves sothat they can enter the center section 3226.

In alternate embodiments of the device 3200, a series or array ofpassages 3240 are formed in a device, such that a screen or filter canbe formed. This allows the device to have a much greater flow capacitywhile maintaining a desired restriction of the maximum size of particlescapable of passing the through the device.

In another alternate embodiment, a device has a series of passages 3240which are arranged to position either the inlet and/or the outletapertures, to control the flow either upstream and/or downstream of thedevice. Also, one or more of the passages 3240 can be connected togetherto allow flow to continue to outlets even with one or more inlets areblocked or restricted. In certain embodiments all the passages areconnected by a manifold to prevent blockage and clogging and to allow aneven distribution of flow to be maintained across the outlets.

Such a manifold or a spacer layer can be employed to allow the earlierlayers (upstream layers) in a flow to serve as a pre-filter or a stagedfilter for the later (downstream) layers. For example, a first layercould be employed with a set of 20 μm pores, spaced from a second layerby a 20 μm spacer layer(s), and where the second layer has a set of 5 μmpores.

Some of the alternate embodiments of the invention have a differentarrangement of the passage 3240. In such embodiments the second layeraperture sections 3228 and 3229, shown in FIG. 32A positioned about thecenter section 3226, have a different size and shape from that shown.Namely, to reduce the potential for blocking or clogging, the aperturesection which is adjacent to the inlet (or both apertures, if the flowcan reverse), is sized smaller than the adjacent aperture (apertures3214 or 3234), such that a stepped or funnel-shaped opening is formed atthe inlet (and outlet if required). By arranging the inlet in thismanner, larger particles can be restrained away from the center section2226 reducing or eliminating the potential for clogging or blockage.

In still another alternative embodiment, the device includes a firstlayer and a third layer structures that overlap to define the centerportion of the connecting opening of the second layer. These embodimentsare similar to the embodiment of FIGS. 32A and 32B except that thesecond layer does not include structure that defines the connectingopening and the first layer and the third layers lack structure whichdefines the apertures at the inlet and the outlet. This maximizes thesize of the inlet and outlet while retaining the size of the centerportion of the second layer. In other embodiments only the inlet or theoutlet uses this configuration.

It should be clear to one skilled in the art that the device 3200 andits alternate embodiments can be formed by embodiments of thefabrication methods set forth herein.

Funnel and Nozzle Shaped Passage Embodiments

Another embodiment of the Applicants' invention has an apparatus with apassage formed so that it varies in size (e.g. cross-section) along itslength. Among other things, this allows the size of the inlet and outletto vary from each other. The passage can be formed in a funnel shape,with a decreasing or increasing cross-section between the inlet andoutlet.

An advantage to a funnel-shaped passage is that it is capable ofreducing clogging or blockage of the passage. This is achieved byrestraining larger particles at portions of the passage with largercross-sections (e.g. near the inlet), preventing the larger particlesfrom reaching the narrower regions of the passage, yet allowing smallerparticles to continue through the passage. That is, the funnel-shapedpassage functions effectively as a pre-filter or a staged filter.

One embodiment of a funnel-shaped passage is shown in FIG. 33 where adevice 3300 includes a series of layers 3310 defining a passage 3320.The layers 3310 include a first or base layer 3312 having a firstopening or gap 3314 and a second layer 3316 with a second opening or gap3318. The openings are staggered to form a defined opening 3319 at theintersection of the layers 3312 and 3316. While the size and shape ofeach opening can vary, in this embodiment the openings 3314 and 3318each have a width of a distance A33 and the defined opening 3319 has awidth of a distance B33.

The passage 3320 includes an inlet 3322 and an outlet 3324. The inlet3322 has a greater width (or cross-section) than the outlet 3324.Between the inlet 3322 and the outlet 3324, the layers 3310 are arrangedto define ever smaller openings starting at the inlet 3322 going to theoutlet 3324, such that a funnel shape is formed. The funnel shape of thepassage 3320 functions to restrain larger particles prior to reaching,and potentially clogging, the outlet 3324. At the same time, the funnelshape of the passage 3320 allows sufficiently small particles tocontinue past any restrained particles and through the passage 3320 tothe outlet 3324.

Depending on the embodiment, the outlet 3324 can be formed to have awidth B33 that is less than the MFS of the layers. With the openings3314 and 3318 having a minimum width A33 equal to the MFS, by offsettingor staggering the layers 3312 and 3316, the defined opening 3319 at theintersection of the layers 3312 and 3316, is capable of having a widthB33 that is less than the MFS. The smaller the width of the definedopening 3319 (and therefore of the outlet 3324), the greater the degreeof filtration achieved by minimizing the size of the particles which maypass through the passage 3320.

It should be noted that a variety of alternate embodiments to that shownin FIG. 33 are possible. The dimensions of the passage 3320 and itsfeatures can vary such that the passage 3320 can be specifically shapedand sized according the particular particles encountered in specificuses. For example, more or less layers 3310 can be employed to definethe length of the passage 3320 and the width of the openings in thelayers can be varied to define the slope of the funnel portion of thepassage 3320. Some embodiments include a device having a series or anarray of funnel-shaped passages, to form a grid, screen or filter. Inother embodiments, the direction of the flow can be reversed so that theflow enters the passage 3320 at the outlet 3324 and exits at the inlet3322. Changing the flow direction can allow the passage 3320 to functionas a nozzle (as further described herein).

The device 3300 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

Another embodiment of the invention has an apparatus with a passageformed in a nozzle shape, so that it varies in size (e.g. cross-section)along its length from wide to narrow to wide again. This embodiment issimilar to the funnel-shaped embodiments (described herein), except thatthe passage again widens out from its narrowest portion to form a nozzleshape.

An advantage of a nozzle-shaped passage is that it can be used inapplications capable of providing specific products. For example, in oneapplication an embodiment of the invention has an array of nozzles formicro-particle generation and encapsulation. This can be done withsupercritical CO₂, where by flashing the fluid through an appropriatenozzle-shaped passage, instantaneous precipitation is achieved at thenozzle throat. With a fluid having multiple solutes, the solutesco-precipitate, and by controlling concentrations, the process caneffectively micro-encapsulate one solute within the other. As furtherdescribe herein, such results can also be achieve with a funnel-shapedpassage.

Another advantage to a nozzle-shaped passage is that, like thefunnel-shaped passage it is capable of reducing clogging or blockage ofthe passage. This is achieved by restraining larger particles atportions of the passage with larger cross-sections and preventing themfrom blocking or clogging the narrower regions, while allowing continuedflow of smaller particles. Like with the funnel-shaped embodiments, thenozzle-shape passage functions effectively as a pre-filter or a stagedfilter.

One embodiment of a nozzle-shaped passage is shown in FIG. 34 where adevice 3400 includes a series of layers 3410 defining a passage 3420.The layers 3410 include a first layer 3412 having a first opening or gap3414 and a second layer 3416 with a second opening or gap 3418. Theopenings are staggered to form a defined opening 3419 at theintersection of the layers. While the size and shape of the openings canvary, in the embodiment shown the openings 3414 and 3418 have a width ofa distance A34 and the defined opening 3419 has a width of a distanceB34.

The passage 3420 includes an inlet 3422, a throat 3424 and an outlet3426. The inlet 3422 and outlet 3426 have greater widths than the throat3424. Between the inlet 3422 and the throat 3424, the layers 3410 arearranged to define ever smaller openings starting at the inlet 3422going to the throat 3424, such that an inlet funnel 3428 is formed. Theinlet funnel 3328 functions to restrain larger particles prior to theirreaching and potentially clogging the throat 3424, while allowingsufficiently small particles to continue through the throat 3424. Fromthe throat 3424 to the outlet 3426, the layers 3410 are arranged todefine ever larger openings starting at the throat 3424 going to theoutlet 3426, such that an outlet funnel 3329 is formed. Combined, theinlet funnel 3428 and the outlet funnel 3429 shape the passage 3420 toform a nozzle shape.

Depending on the embodiment, the throat 3424 can be formed to have awidth B34 that is less than the MFS of the layers. With the openings3414 and 3418 being a having a minimum width A34 of the MFS, byoffsetting or staggering the layers 3412 and 3416, the defined opening3419 positioned at the intersection of the layers 3412 and 3416, iscapable of having a width B34 that is less than the MFS. The smaller thewidth of the defined opening 3419, and therefore of the throat 3424, thegreater the degree of filtration achieved by minimizing the size of theparticles which may pass through the passage 3420.

It should be noted that a variety of alternate embodiments to that shownin FIG. 34 are possible. The dimensions of the passage 3420 and itsfeatures can vary such that the passage 3420 can be specifically shapedand sized according the particular particles encountered in specificuses. For example, more or less layers 3410 can be employed to definethe length of the passage 3420 and the width of the openings in thelayers can be varied to define the slope of the nozzle portion of thepassage 3420. Some embodiments include a device having a series or anarray of nozzle-shaped passages, to form a grid, screen or filter. Inother embodiments, the passage 3420 can have just the one funnel-shapedportion to form the nozzle. An example of such a single funnel nozzle isthe embodiment of the device 3300 shown in FIG. 33.

The device 3400 and its alternate embodiments can be formed byembodiments of the fabrication methods set forth herein.

The patent applications and patents set forth below are herebyincorporated by reference herein as if set forth in full. The teachingsin these incorporated applications can be combined with the teachings ofthe instant application in many ways: For example, enhanced methods ofproducing structures may be derived from some combinations of teachings,enhanced structures may be obtainable, enhanced apparatus may bederived, and the like. 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In some embodiments, two materials may be deposited in association withindividual layers but additional materials may be added to the overallstructure by using different pairs of materials on different layers. Forexample, some layers may include copper and a dielectric while otherlayers may include nickel and copper. After the formation of thestructure is completed, the copper may be removed as a sacrificialmaterial which leaves behind a nickel and dielectric structure withhollowed out regions and/or a nickel, dielectric, and copper structureif copper is entrapped by regions of nickel and/or dielectric material.

In some embodiments, mesoscale and microscale multilayerthree-dimensional structures or devices are electrochemically formedwherein one or more dielectric materials are incorporated into thestructure with the formation of each layer. Seed layers, and potentiallyseed layer stacks of multiple materials (e.g. adhesion layer materialand seed layer material), are provided during the formation of layers toensure that a surface is capable of electrochemically receiving depositsof material. On some layers seed layer material is not deposited as aplanar layer but is instead deposited over exposed regions of asubstrate and over one or more previously deposited patterns of materialon the layer. Additional deposition of material occurs over the seedlayer material and planarization operations are used to remove seedlayer material deposited on previously deposited materials on the layer.

In some embodiments three-dimensional structures are electrochemicallyfabricated by depositing a first material onto previously depositedmaterial through voids in a patterned mask where the patterned mask isat least temporarily adhered to a substrate or previously formed layerof material and is formed and patterned onto the substrate via atransfer tool patterned to enable transfer of a desired pattern ofprecursor masking material. In some embodiments the precursor materialis transformed into masking material after transfer to the substratewhile in other embodiments the precursor is transformed during or beforetransfer. In some embodiments layers are formed one on top of another tobuild up multi-layer structures. In some embodiments the mask materialacts as a build material while in other embodiments the mask material isreplaced each layer by a different material which may, for example, beconductive or dielectric.

In some embodiments three-dimensional structures are electrochemicallyfabricated by depositing a first material onto previously depositedmaterial through voids in a patterned mask where the patterned mask isat least temporarily adhered to previously deposited material and isformed and patterned directly from material selectively dispensed from acomputer controlled dispensing device (e.g. an ink jet nozzle or arrayor an extrusion device). In some embodiments layers are formed one ontop of another to build up multi-layer structures. In some embodimentsthe mask material acts as a build material while in other embodimentsthe mask material is replaced each layer by a different material whichmay, for example, be conductive or dielectric.

It will be understood by those of skill in the art that additionaloperations may be used in variations of the above presented embodiments.These additional operations may perform cleaning functions (e.g. betweenthe primary operations discussed above), they may perform activationfunctions and monitoring functions.

In view of the teachings herein, many further embodiments, alternativesin design and uses of the invention will be apparent to those of skillin the art. As such, it is not intended that the invention be limited tothe particular illustrative embodiments, alternatives, and usesdescribed above but instead that it be solely limited by the claimspresented hereafter.

1. A layered three-dimensional structure having a minimum feature size,the layered three-dimensional structure comprising: a first element; anda second element positioned adjacent to the first element to define athird element positioned between the first element and the secondelement, wherein the third element is sized less than the minimumfeature size.
 2. The layered three-dimensional structure of claim 1,wherein the third element is a void.
 3. The layered three-dimensionalstructure of claim 1, wherein the third element is a gap.
 4. The layeredthree-dimensional structure of claim 2, wherein the first elementcomprises a material layer, and wherein the second element comprises amaterial layer.
 5. The layered three-dimensional structure of claim 4,wherein the first element is positioned substantially along a firstplane, wherein the second element is positioned substantially along asecond plane, and wherein the first plane is substantially parallel andadjacent the second plane.
 6. The layered three-dimensional structure ofclaim 2, wherein the first element comprises a layered structure, andwherein the second element comprises a layered structure.
 7. The layeredthree-dimensional structure of claim 2, wherein the first element iscapable of moving relative to the second element.
 8. The layeredthree-dimensional structure of claim 1, wherein the third element is anopening.
 9. The layered three-dimensional structure of claim 8, whereinthe third element is a pore.
 10. The layered three-dimensional structureof claim 8, wherein the first element abuts the second element.
 11. Thelayered three-dimensional structure of claim 8, wherein the firstelement comprises a material layer, and wherein the second elementcomprises a material layer.
 12. The layered three-dimensional structureof claim 11, wherein the second element is positioned upon the firstelement, so that the second element and the first element are incontact.
 13. The layered three-dimensional structure of claim 8, whereinthe first element comprises a layered structure, and wherein the secondelement comprises a layered structure.
 14. The layered three-dimensionalstructure of claim 8, wherein the opening is capable of providingpassage of at least one of a particle, a gas and a fluid.
 15. A layeredthree-dimensional structure having a minimum feature size, the layeredthree-dimensional structure comprising: a first layer defining a firstopening, wherein the first opening is at least as large as the minimumfeature size; and a second layer positioned adjacent to the first layer,wherein the second layer defines a second opening at least as large asthe minimum feature size, wherein the second opening is positionedadjacent the first opening to define a third opening between the firstopening and the second opening, and wherein the third opening is capableof being sized less than the minimum feature size.
 16. The layeredthree-dimensional structure of claim 15, wherein the third opening issized less than the minimum feature size.
 17. The layeredthree-dimensional structure of claim 15, wherein the second layer abutsthe first layer.
 18. The layered three-dimensional structure of claim15, wherein the second opening abuts the first opening.
 19. The layeredthree-dimensional structure of claim 18, wherein the second openingoverlaps the first opening.
 20. The layered three-dimensional structureof claim 18, wherein the first layer comprises at least one of gold,silver, nickel and copper.
 21. The layered three-dimensional structureof claim 18, wherein the first layer comprises nickel.
 22. The layeredthree-dimensional structure of claim 20, wherein the second layercomprises at least one of gold, silver, nickel and copper.
 23. Thelayered three-dimensional structure of claim 21, wherein the secondlayer comprises nickel.
 24. The layered three-dimensional structure ofclaim 18, wherein the first layer has a thickness between 1 μm and 20μm, and wherein the second layer has a thickness between 1 μm and 20 μm.25. The layered three-dimensional structure of claim 24, wherein thefirst layer is about 2 μm thick, and wherein the second layer is about 2μm thick.
 26. The layered three-dimensional structure of claim 15,wherein the first layer is positioned substantially along a first plane,wherein the second layer is positioned substantially along a secondplane, and wherein the first plane is substantially parallel to thesecond plane.
 27. The layered three-dimensional structure of claim 26,wherein the first plane is parallel to the second plane.
 28. The layeredthree-dimensional structure of claim 15, wherein the first layercomprises a first fixed portion and a first movable portion positionedon the opposite side of the first opening from the first fixed portion,wherein the second layer comprises a second fixed portion and a secondmovable portion positioned on the opposite side of the second openingfrom the second fixed portion, wherein the second fixed portion abutsthe first fixed portion to form a fixed element, wherein the secondmovable portion abuts the second movable portion to form a movableelement, and wherein the movable element is capable of moving relativeto the fixed element.
 29. The layered three-dimensional structure ofclaim 28, wherein the layered three-dimensional structure is anactuator, wherein the fixed element is an electrode, and wherein themovable element is an electrode.
 30. The layered three-dimensionalstructure of claim 29, wherein the actuator is at least one of avertical comb actuator, horizontal comb actuator and a capacitance typeactuator.
 31. The layered three-dimensional structure of claim 30,wherein at least a portion of the fixed element is electricallyconductive, wherein at least a portion of the movable element iselectrically conductive, and wherein the three-dimensional structure iscapable of applying an electrical differential between the fixed elementand the movable element to provide an electrostatic force.
 32. A layeredthree-dimensional structure having a minimum feature size, the layeredthree-dimensional structure comprising: a first layer having a framestructure defining an array of first openings, wherein each firstopening is at least as large as the minimum feature size; and a secondlayer having a frame structure defining an array of second openings,wherein each second opening is at least as large as the minimum featuresize, wherein the second layer is positioned at least adjacent to thefirst layer, wherein the array of second openings is positioned adjacentthe array of first openings to define an array of third openings betweenthe array of first openings and the array of second openings, andwherein each third opening is capable of being sized less than theminimum feature size.
 33. The three-dimensional structure of claim 32,wherein at least one of the third openings are sized less than theminimum feature size.
 34. The layered three-dimensional structure ofclaim 32, wherein the second layer is upon the first layer.
 35. Thelayered three-dimensional structure of claim 32, wherein the secondopenings contact the first openings so that the second openings overlapthe first openings.
 36. The layered three-dimensional structure of claim32 wherein the three-dimensional structure is a filter.
 37. The layeredthree-dimensional structure of claim 36, wherein the third openings arepores in the filter.
 38. The layered three-dimensional structure ofclaim 32, wherein the first layer comprises at least one of gold,silver, nickel and copper.
 39. The layered three-dimensional structureof claim 32, wherein the first layer comprises nickel.
 40. The layeredthree-dimensional structure of claim 38, wherein the second layercomprises at least one of gold, silver, nickel and copper.
 41. Thelayered three-dimensional structure of claim 40, wherein the secondlayer comprises nickel.
 42. The layered three-dimensional structure ofclaim 32, wherein the first layer has a thickness between 1 μm and 20μm, and wherein the second layer has a thickness between 1 μm and 20 μm.43. The layered three-dimensional structure of claim 42, wherein thefirst layer is about 2 μm thick, and wherein the second layer is about 2μm thick.